asp.net中SQLHelper类实现数据库操作

自己的DBHelper类

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 代码如下 复制代码
 public class DBHelper
     {
         /// <summary>
         /// 从Web.config配置文件中读取数据库连接
         /// </summary>
         private static string connectionStrings = ConfigurationManager.ConnectionStrings["MyConnectionString"].ToString();
 
         public static string ConnectionStrings
         {
             get { return DBHelper.connectionStrings; }
         }
         /// <summary>
         /// 打开数据库连接
         /// </summary>
         /// <param name="cmdText"></param>
         /// <param name="cmdType"></param>
         /// <param name="param"></param>
         /// <returns></returns>
         private static SqlCommand GetCommand(string strSql, CommandType cmdType, SqlParameter[] parameters)
         {
             SqlCommand cmd = new SqlCommand();
             cmd.Connection = new SqlConnection(connectionStrings);//连接配置文件
             try
             {
                 cmd.CommandText = strSql;//传入SQL语句或存储过程
                 cmd.CommandType = cmdType;//
                 if (parameters != null)
                 {
                     foreach (SqlParameter p in parameters)
                     {
                         cmd.Parameters.Add(p);
                     }
                 }
             }
             finally
             {
                 cmd.Connection.Open();//打开连接
             }
 
             return cmd;
         }
 
         /// <summary>
         /// 返回受影响的行数
         /// </summary>
         /// <param name="cmdText"></param>
         /// <param name="cmdType"></param>
         /// <param name="param"></param>
         /// <returns></returns>
         public static int ExecuteQuery(string strSql, CommandType cmdType, params SqlParameter[] param)
         {
             SqlCommand cmd = GetCommand(strSql, cmdType, param);
             int result = 0;
             try
             {
                 result = cmd.ExecuteNonQuery();
             }
             finally
             {
                 cmd.Connection.Close();
             }
             return result;
         }
         /// <summary>
         /// 返回一行一列
         /// </summary>
         /// <param name="cmdText"></param>
         /// <param name="cmdType"></param>
         /// <param name="param"></param>
         /// <returns></returns>
         public static int ExecuteScalar(string strSql, CommandType cmdType, params SqlParameter[] param)
         {
             SqlCommand cmd = GetCommand(strSql, cmdType, param);
             int result = 0;
             try
             {
                 result = (int)cmd.ExecuteScalar();
             }
             finally
             {
                 cmd.Connection.Close();
             }
             return result;
         }
 
         /// <summary>
         /// 返回集合(dataSet)
         /// </summary>
         /// <param name="cmdText"></param>
         /// <param name="cmdType"></param>
         /// <param name="param"></param>
         /// <returns></returns>
         public static DataSet ExecuteDataSet(string strSql, CommandType cmdType, params SqlParameter[] parameters)
         {
             DataSet ds = new DataSet();
            
             SqlCommand cmd = GetCommand(strSql, cmdType, parameters);
             try
             {
                 SqlDataAdapter adapter = new SqlDataAdapter(cmd);
                 adapter.Fill(ds);
             }
             finally
             {
                 cmd.Connection.Close();//关闭连接
             }
             return ds;
         }
 
         /// <summary>
         /// 返回某个对象(dataTable)
         /// </summary>
         /// <param name="cmdText"></param>
         /// <param name="cmdType"></param>
         /// <param name="param"></param>
         /// <returns></returns>
         public static DataTable ExecuteDataTable(string strSql, CommandType cmdType, params SqlParameter[] parameters)
         {
             SqlCommand cmd = GetCommand(strSql, cmdType, parameters);
             DataSet ds = new DataSet();
             try
             {
                 SqlDataAdapter adapter = new SqlDataAdapter(cmd);
                 adapter.Fill(ds);
             }
             finally
             {
                 cmd.Connection.Close();
             }
             return ds.Tables[0];
         }
     }

SQLHelper类代码

 

 代码如下 复制代码
public class SQLHelper
     {
         /// <summary>
         /// SqlServer数据访问帮助类
         /// </summary>
         public sealed class SqlHelper
         {
             #region 私有构造函数和方法
 
             private SqlHelper() { }
 
             /// <summary>
             /// 将SqlParameter参数数组(参数值)分配给SqlCommand命令.
             /// 这个方法将给任何一个参数分配DBNull.Value;
             /// 该操作将阻止默认值的使用.
             /// </summary>
             /// <param name="command">命令名</param>
             /// <param name="commandParameters">SqlParameters数组</param>
             private static void AttachParameters(SqlCommand command, SqlParameter[] commandParameters)
             {
                 if (command == null) throw new ArgumentNullException("command");
                 if (commandParameters != null)
                 {
                     foreach (SqlParameter p in commandParameters)
                     {
                         if (p != null)
                         {
                             // 检查未分配值的输出参数,将其分配以DBNull.Value.
                             if ((p.Direction == ParameterDirection.InputOutput || p.Direction == ParameterDirection.Input) &&
                                 (p.Value == null))
                             {
                                 p.Value = DBNull.Value;
                             }
                             command.Parameters.Add(p);
                         }
                     }
                 }
             }
 
             /// <summary>
             /// 将DataRow类型的列值分配到SqlParameter参数数组.
             /// </summary>
             /// <param name="commandParameters">要分配值的SqlParameter参数数组</param>
             /// <param name="dataRow">将要分配给存储过程参数的DataRow</param>
             private static void AssignParameterValues(SqlParameter[] commandParameters, DataRow dataRow)
             {
                 if ((commandParameters == null) || (dataRow == null))
                 {
                     return;
                 }
 
                 int i = 0;
                 // 设置参数值
                 foreach (SqlParameter commandParameter in commandParameters)
                 {
                     // 创建参数名称,如果不存在,只抛出一个异常.
                     if (commandParameter.ParameterName == null ||
                         commandParameter.ParameterName.Length <= 1)
                         throw new Exception(
                             string.Format("请提供参数{0}一个有效的名称{1}.", i, commandParameter.ParameterName));
                     // 从dataRow的表中获取为参数数组中数组名称的列的索引.
                     // 如果存在和参数名称相同的列,则将列值赋给当前名称的参数.
                     if (dataRow.Table.Columns.IndexOf(commandParameter.ParameterName.Substring(1)) != -1)
                         commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];
                     i++;
                 }
             }
 
             /// <summary>
             /// 将一个对象数组分配给SqlParameter参数数组.
             /// </summary>
             /// <param name="commandParameters">要分配值的SqlParameter参数数组</param>
             /// <param name="parameterValues">将要分配给存储过程参数的对象数组</param>
             private static void AssignParameterValues(SqlParameter[] commandParameters, object[] parameterValues)
             {
                 if ((commandParameters == null) || (parameterValues == null))
                 {
                     return;
                 }
 
                 // 确保对象数组个数与参数个数匹配,如果不匹配,抛出一个异常.
                 if (commandParameters.Length != parameterValues.Length)
                 {
                     throw new ArgumentException("参数值个数与参数不匹配.");
                 }
 
                 // 给参数赋值
                 for (int i = 0, j = commandParameters.Length; i < j; i++)
                 {
                     // If the current array value derives from IDbDataParameter, then assign its Value property
                     if (parameterValues[i] is IDbDataParameter)
                     {
                         IDbDataParameter paramInstance = (IDbDataParameter)parameterValues[i];
                         if (paramInstance.Value == null)
                         {
                             commandParameters[i].Value = DBNull.Value;
                         }
                         else
                         {
                             commandParameters[i].Value = paramInstance.Value;
                         }
                     }
                     else if (parameterValues[i] == null)
                     {
                         commandParameters[i].Value = DBNull.Value;
                     }
                     else
                     {
                         commandParameters[i].Value = parameterValues[i];
                     }
                 }
             }
 
             /// <summary>
             /// 预处理用户提供的命令,数据库连接/事务/命令类型/参数
             /// </summary>
             /// <param name="command">要处理的SqlCommand</param>
             /// <param name="connection">数据库连接</param>
             /// <param name="transaction">一个有效的事务或者是null值</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
             /// <param name="commandText">存储过程名或都T-SQL命令文本</param>
             /// <param name="commandParameters">和命令相关联的SqlParameter参数数组,如果没有参数为'null'</param>
             /// <param name="mustCloseConnection"><c>true</c> 如果连接是打开的,则为true,其它情况下为false.</param>
             private static void PrepareCommand(SqlCommand command, SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, out bool mustCloseConnection)
             {
                 if (command == null) throw new ArgumentNullException("command");
                 if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");
 
                 // If the provided connection is not open, we will open it
                 if (connection.State != ConnectionState.Open)
                 {
                     mustCloseConnection = true;
                     connection.Open();
                 }
                 else
                 {
                     mustCloseConnection = false;
                 }
 
                 // 给命令分配一个数据库连接.
                 command.Connection = connection;
 
                 // 设置命令文本(存储过程名或SQL语句)
                 command.CommandText = commandText;
 
                 // 分配事务
                 if (transaction != null)
                 {
                     if (transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                     command.Transaction = transaction;
                 }
 
                 // 设置命令类型.
                 command.CommandType = commandType;
 
                 // 分配命令参数
                 if (commandParameters != null)
                 {
                     AttachParameters(command, commandParameters);
                 }
                 return;
             }
 
             #endregion 私有构造函数和方法结束
 
             #region 数据库连接
             /// <summary>
             /// 一个有效的数据库连接字符串
             /// </summary>
             /// <returns></returns>
             public static string GetConnSting()
             {
                 return ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
             }
             /// <summary>
             /// 一个有效的数据库连接对象
             /// </summary>
             /// <returns></returns>
             public static SqlConnection GetConnection()
             {
                 SqlConnection Connection = new SqlConnection(SqlHelper.GetConnSting());
                 return Connection;
             }
             #endregion
 
             #region ExecuteNonQuery命令
 
             /// <summary>
             /// 执行指定连接字符串,类型的SqlCommand.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders");
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
             /// <param name="commandText">存储过程名称或SQL语句</param>
             /// <returns>返回命令影响的行数</returns>
             public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText)
             {
                 return ExecuteNonQuery(connectionString, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定连接字符串,类型的SqlCommand.如果没有提供参数,不返回结果.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本, 其它.)</param>
             /// <param name="commandText">存储过程名称或SQL语句</param>
             /// <param name="commandParameters">SqlParameter参数数组</param>
             /// <returns>返回命令影响的行数</returns>
             public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
 
                 using (SqlConnection connection = new SqlConnection(connectionString))
                 {
                     connection.Open();
 
                     return ExecuteNonQuery(connection, commandType, commandText, commandParameters);
                 }
             }
 
             /// <summary>
             /// 执行指定连接字符串的存储过程,将对象数组的值赋给存储过程参数,
             /// 此方法需要在参数缓存方法中探索参数并生成参数.
             /// </summary>
             /// <remarks>
             /// 这个方法没有提供访问输出参数和返回值.
             /// 示例: 
             ///  int result = ExecuteNonQuery(connString, "PublishOrders", 24, 36);
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串/param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="parameterValues">分配到存储过程输入参数的对象数组</param>
             /// <returns>返回受影响的行数</returns>
             public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果存在参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从探索存储过程参数(加载到缓存)并分配给存储过程参数数组.
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数情况下
                     return ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders");
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <returns>返回影响的行数</returns>
             public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText)
             {
                 return ExecuteNonQuery(connection, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
             /// <param name="commandText">T存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">SqlParamter参数数组</param>
             /// <returns>返回影响的行数</returns>
             public static int ExecuteNonQuery(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
 
                 // 创建SqlCommand命令,并进行预处理
                 SqlCommand cmd = new SqlCommand();
                 bool mustCloseConnection = false;
                 PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // Finally, execute the command
                 int retval = cmd.ExecuteNonQuery();
 
                 // 清除参数,以便再次使用.
                 cmd.Parameters.Clear();
                 if (mustCloseConnection)
                     connection.Close();
                 return retval;
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,将对象数组的值赋给存储过程参数.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值
             /// 示例: 
             ///  int result = ExecuteNonQuery(conn, "PublishOrders", 24, 36);
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回影响的行数</returns>
             public static int ExecuteNonQuery(SqlConnection connection, string spName, params object[] parameterValues)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 给存储过程分配参数值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行带事务的SqlCommand.
             /// </summary>
             /// <remarks>
             /// 示例.: 
             ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders");
             /// </remarks>
             /// <param name="transaction">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <returns>返回影响的行数/returns>
             public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText)
             {
                 return ExecuteNonQuery(transaction, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行带事务的SqlCommand(指定参数).
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="transaction">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型(存储过程,命令文本或其它.)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">SqlParamter参数数组</param>
             /// <returns>返回影响的行数</returns>
             public static int ExecuteNonQuery(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
 
                 // 预处理
                 SqlCommand cmd = new SqlCommand();
                 bool mustCloseConnection = false;
                 PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // 执行
                 int retval = cmd.ExecuteNonQuery();
 
                 // 清除参数集,以便再次使用.
                 cmd.Parameters.Clear();
                 return retval;
             }
 
             /// <summary>
             /// 执行带事务的SqlCommand(指定参数值).
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值
             /// 示例: 
             ///  int result = ExecuteNonQuery(conn, trans, "PublishOrders", 24, 36);
             /// </remarks>
             /// <param name="transaction">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回受影响的行数</returns>
             public static int ExecuteNonQuery(SqlTransaction transaction, string spName, params object[] parameterValues)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     return ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
                 }
             }
 
             #endregion ExecuteNonQuery方法结束
 
             #region ExecuteDataset方法
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText)
             {
                 return ExecuteDataset(connectionString, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 示例:
             ///  DataSet ds = ExecuteDataset(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">SqlParamters参数数组</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
 
                 // 创建并打开数据库连接对象,操作完成释放对象.
                 using (SqlConnection connection = new SqlConnection(connectionString))
                 {
                     connection.Open();
 
                     // 调用指定数据库连接字符串重载方法.
                     return ExecuteDataset(connection, commandType, commandText, commandParameters);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,直接提供参数值,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值.
             /// 示例:
             ///  DataSet ds = ExecuteDataset(connString, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中检索存储过程参数
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     // 给存储过程参数分配值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText)
             {
                 return ExecuteDataset(connection, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,指定存储过程参数,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  DataSet ds = ExecuteDataset(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <param name="commandParameters">SqlParamter参数数组</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
 
                 // 预处理
                 SqlCommand cmd = new SqlCommand();
                 bool mustCloseConnection = false;
                 PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // 创建SqlDataAdapter和DataSet.
                 using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                 {
                     DataSet ds = new DataSet();
 
                     // 填充DataSet.
                     da.Fill(ds);
 
                     cmd.Parameters.Clear();
 
                     if (mustCloseConnection)
                         connection.Close();
 
                     return ds;
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,指定参数值,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输入参数和返回值.
             /// 示例.: 
             ///  DataSet ds = ExecuteDataset(conn, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(SqlConnection connection, string spName, params object[] parameterValues)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 比缓存中加载存储过程参数
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 给存储过程参数分配值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return ExecuteDataset(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定事务的命令,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="transaction">事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText)
             {
                 return ExecuteDataset(transaction, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定事务的命令,指定参数,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  DataSet ds = ExecuteDataset(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="transaction">事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <param name="commandParameters">SqlParamter参数数组</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
 
                 // 预处理
                 SqlCommand cmd = new SqlCommand();
                 bool mustCloseConnection = false;
                 PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // 创建 DataAdapter & DataSet
                 using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                 {
                     DataSet ds = new DataSet();
                     da.Fill(ds);
                     cmd.Parameters.Clear();
                     return ds;
                 }
             }
 
             /// <summary>
             /// 执行指定事务的命令,指定参数值,返回DataSet.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输入参数和返回值.
             /// 示例.: 
             ///  DataSet ds = ExecuteDataset(trans, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="transaction">事务</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回一个包含结果集的DataSet</returns>
             public static DataSet ExecuteDataset(SqlTransaction transaction, string spName, params object[] parameterValues)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 给存储过程参数分配值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
                 }
             }
 
             #endregion ExecuteDataset数据集命令结束
 
             #region ExecuteReader 数据阅读器
 
             /// <summary>
             /// 枚举,标识数据库连接是由SqlHelper提供还是由调用者提供
             /// </summary>
             private enum SqlConnectionOwnership
             {
                 /// <summary>由SqlHelper提供连接</summary>
                 Internal,
                 /// <summary>由调用者提供连接</summary>
                 External
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的数据阅读器.
             /// </summary>
             /// <remarks>
             /// 如果是SqlHelper打开连接,当连接关闭DataReader也将关闭.
             /// 如果是调用都打开连接,DataReader由调用都管理.
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="transaction">一个有效的事务,或者为 'null'</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <param name="commandParameters">SqlParameters参数数组,如果没有参数则为'null'</param>
             /// <param name="connectionOwnership">标识数据库连接对象是由调用者提供还是由SqlHelper提供</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             private static SqlDataReader ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, string commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
 
                 bool mustCloseConnection = false;
                 // 创建命令
                 SqlCommand cmd = new SqlCommand();
                 try
                 {
                     PrepareCommand(cmd, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
                     // 创建数据阅读器
                     SqlDataReader dataReader;
 
                     if (connectionOwnership == SqlConnectionOwnership.External)
                     {
                         dataReader = cmd.ExecuteReader();
                     }
                     else
                     {
                         dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                     }
 
                     // 清除参数,以便再次使用..
                     // HACK: There is a problem here, the output parameter values are fletched
                     // when the reader is closed, so if the parameters are detached from the command
                     // then the SqlReader can? set its values.
                     // When this happen, the parameters can? be used again in other command.
                     bool canClear = true;
                     foreach (SqlParameter commandParameter in cmd.Parameters)
                     {
                         if (commandParameter.Direction != ParameterDirection.Input)
                             canClear = false;
                     }
 
                     if (canClear)
                     {
                         cmd.Parameters.Clear();
                     }
 
                     return dataReader;
                 }
                 catch
                 {
                     if (mustCloseConnection)
                         connection.Close();
                     throw;
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的数据阅读器.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText)
             {
                 return ExecuteReader(connectionString, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的数据阅读器,指定参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(connString, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <param name="commandParameters">SqlParamter参数数组(new SqlParameter("@prodid", 24))</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 SqlConnection connection = null;
                 try
                 {
                     connection = new SqlConnection(connectionString);
                     connection.Open();
 
                     return ExecuteReader(connection, null, commandType, commandText, commandParameters, SqlConnectionOwnership.Internal);
                 }
                 catch
                 {
                     // If we fail to return the SqlDatReader, we need to close the connection ourselves
                     if (connection != null) connection.Close();
                     throw;
                 }
 
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的数据阅读器,指定参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(connString, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的数据阅读器.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名或T-SQL语句</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText)
             {
                 return ExecuteReader(connection, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandParameters">SqlParamter参数数组</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 return ExecuteReader(connection, (SqlTransaction)null, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
             }
 
             /// <summary>
             /// [调用者方式]执行指定数据库连接对象的数据阅读器,指定参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(conn, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">T存储过程名</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(SqlConnection connection, string spName, params object[] parameterValues)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return ExecuteReader(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText)
             {
                 return ExecuteReader(transaction, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///   SqlDataReader dr = ExecuteReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
 
                 return ExecuteReader(transaction.Connection, transaction, commandType, commandText, commandParameters, SqlConnectionOwnership.External);
             }
 
             /// <summary>
             /// [调用者方式]执行指定数据库事务的数据阅读器,指定参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  SqlDataReader dr = ExecuteReader(trans, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReader(SqlTransaction transaction, string spName, params object[] parameterValues)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     AssignParameterValues(commandParameters, parameterValues);
 
                     return ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     return ExecuteReader(transaction, CommandType.StoredProcedure, spName);
                 }
             }
 
             #endregion ExecuteReader数据阅读器
 
             #region ExecuteScalar 返回结果集中的第一行第一列
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount");
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText)
             {
                 // 执行参数为空的方法
                 return ExecuteScalar(connectionString, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,指定参数,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(connString, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 // 创建并打开数据库连接对象,操作完成释放对象.
                 using (SqlConnection connection = new SqlConnection(connectionString))
                 {
                     connection.Open();
 
                     // 调用指定数据库连接字符串重载方法.
                     return ExecuteScalar(connection, commandType, commandText, commandParameters);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,指定参数值,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(connString, "GetOrderCount", 24, 36);
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     return ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount");
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText)
             {
                 // 执行参数为空的方法
                 return ExecuteScalar(connection, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,指定参数,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(conn, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
 
                 // 创建SqlCommand命令,并进行预处理
                 SqlCommand cmd = new SqlCommand();
 
                 bool mustCloseConnection = false;
                 PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // 执行SqlCommand命令,并返回结果.
                 object retval = cmd.ExecuteScalar();
 
                 // 清除参数,以便再次使用.
                 cmd.Parameters.Clear();
 
                 if (mustCloseConnection)
                     connection.Close();
 
                 return retval;
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,指定参数值,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(conn, "GetOrderCount", 24, 36);
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(SqlConnection connection, string spName, params object[] parameterValues)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     return ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     return ExecuteScalar(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库事务的命令,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount");
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText)
             {
                 // 执行参数为空的方法
                 return ExecuteScalar(transaction, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库事务的命令,指定参数,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(trans, CommandType.StoredProcedure, "GetOrderCount", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
 
                 // 创建SqlCommand命令,并进行预处理
                 SqlCommand cmd = new SqlCommand();
                 bool mustCloseConnection = false;
                 PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // 执行SqlCommand命令,并返回结果.
                 object retval = cmd.ExecuteScalar();
 
                 // 清除参数,以便再次使用.
                 cmd.Parameters.Clear();
                 return retval;
             }
 
             /// <summary>
             /// 执行指定数据库事务的命令,指定参数值,返回结果集中的第一行第一列.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  int orderCount = (int)ExecuteScalar(trans, "GetOrderCount", 24, 36);
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalar(SqlTransaction transaction, string spName, params object[] parameterValues)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // PPull the parameters for this stored procedure from the parameter cache ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     return ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     return ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
                 }
             }
 
             #endregion ExecuteScalar
 
             #region ExecuteXmlReader XML阅读器
             /// <summary>
             /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
             /// <returns>返回XmlReader结果集对象.</returns>
             public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText)
             {
                 // 执行参数为空的方法
                 return ExecuteXmlReader(connection, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  XmlReader r = ExecuteXmlReader(conn, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             /// <returns>返回XmlReader结果集对象.</returns>
             public static XmlReader ExecuteXmlReader(SqlConnection connection, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
 
                 bool mustCloseConnection = false;
                 // 创建SqlCommand命令,并进行预处理
                 SqlCommand cmd = new SqlCommand();
                 try
                 {
                     PrepareCommand(cmd, connection, (SqlTransaction)null, commandType, commandText, commandParameters, out mustCloseConnection);
 
                     // 执行命令
                     XmlReader retval = cmd.ExecuteXmlReader();
 
                     // 清除参数,以便再次使用.
                     cmd.Parameters.Clear();
 
                     return retval;
                 }
                 catch
                 {
                     if (mustCloseConnection)
                         connection.Close();
                     throw;
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  XmlReader r = ExecuteXmlReader(conn, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称 using "FOR XML AUTO"</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回XmlReader结果集对象.</returns>
             public static XmlReader ExecuteXmlReader(SqlConnection connection, string spName, params object[] parameterValues)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     return ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders");
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
             /// <returns>返回XmlReader结果集对象.</returns>
             public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText)
             {
                 // 执行参数为空的方法
                 return ExecuteXmlReader(transaction, commandType, commandText, (SqlParameter[])null);
             }
 
             /// <summary>
             /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  XmlReader r = ExecuteXmlReader(trans, CommandType.StoredProcedure, "GetOrders", new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句 using "FOR XML AUTO"</param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             /// <returns>返回XmlReader结果集对象.</returns>
             public static XmlReader ExecuteXmlReader(SqlTransaction transaction, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
 
                 // 创建SqlCommand命令,并进行预处理
                 SqlCommand cmd = new SqlCommand();
                 bool mustCloseConnection = false;
                 PrepareCommand(cmd, transaction.Connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // 执行命令
                 XmlReader retval = cmd.ExecuteXmlReader();
 
                 // 清除参数,以便再次使用.
                 cmd.Parameters.Clear();
                 return retval;
             }
 
             /// <summary>
             /// 执行指定数据库事务的SqlCommand命令,并产生一个XmlReader对象做为结果集返回,指定参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  XmlReader r = ExecuteXmlReader(trans, "GetOrders", 24, 36);
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             /// <returns>返回一个包含结果集的DataSet.</returns>
             public static XmlReader ExecuteXmlReader(SqlTransaction transaction, string spName, params object[] parameterValues)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     return ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
                 }
             }
 
             #endregion ExecuteXmlReader 阅读器结束
 
             #region FillDataset 填充数据集
             /// <summary>
             /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)</param>
             public static void FillDataset(string connectionString, CommandType commandType, string commandText, DataSet dataSet, string[] tableNames)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (dataSet == null) throw new ArgumentNullException("dataSet");
 
                 // 创建并打开数据库连接对象,操作完成释放对象.
                 using (SqlConnection connection = new SqlConnection(connectionString))
                 {
                     connection.Open();
 
                     // 调用指定数据库连接字符串重载方法.
                     FillDataset(connection, commandType, commandText, dataSet, tableNames);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集.指定命令参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>
             public static void FillDataset(string connectionString, CommandType commandType,
                 string commandText, DataSet dataSet, string[] tableNames,
                 params SqlParameter[] commandParameters)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (dataSet == null) throw new ArgumentNullException("dataSet");
                 // 创建并打开数据库连接对象,操作完成释放对象.
                 using (SqlConnection connection = new SqlConnection(connectionString))
                 {
                     connection.Open();
 
                     // 调用指定数据库连接字符串重载方法.
                     FillDataset(connection, commandType, commandText, dataSet, tableNames, commandParameters);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接字符串的命令,映射数据表并填充数据集,指定存储过程参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  FillDataset(connString, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, 24);
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>   
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             public static void FillDataset(string connectionString, string spName,
                 DataSet dataSet, string[] tableNames,
                 params object[] parameterValues)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (dataSet == null) throw new ArgumentNullException("dataSet");
                 // 创建并打开数据库连接对象,操作完成释放对象.
                 using (SqlConnection connection = new SqlConnection(connectionString))
                 {
                     connection.Open();
 
                     // 调用指定数据库连接字符串重载方法.
                     FillDataset(connection, spName, dataSet, tableNames, parameterValues);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,映射数据表并填充数据集.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>   
             public static void FillDataset(SqlConnection connection, CommandType commandType,
                 string commandText, DataSet dataSet, string[] tableNames)
             {
                 FillDataset(connection, commandType, commandText, dataSet, tableNames, null);
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  FillDataset(conn, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             public static void FillDataset(SqlConnection connection, CommandType commandType,
                 string commandText, DataSet dataSet, string[] tableNames,
                 params SqlParameter[] commandParameters)
             {
                 FillDataset(connection, null, commandType, commandText, dataSet, tableNames, commandParameters);
             }
 
             /// <summary>
             /// 执行指定数据库连接对象的命令,映射数据表并填充数据集,指定存储过程参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  FillDataset(conn, "GetOrders", ds, new string[] {"orders"}, 24, 36);
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             public static void FillDataset(SqlConnection connection, string spName,
                 DataSet dataSet, string[] tableNames,
                 params object[] parameterValues)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (dataSet == null) throw new ArgumentNullException("dataSet");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     FillDataset(connection, CommandType.StoredProcedure, spName, dataSet, tableNames);
                 }
             }
 
             /// <summary>
             /// 执行指定数据库事务的命令,映射数据表并填充数据集.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"});
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>
             public static void FillDataset(SqlTransaction transaction, CommandType commandType,
                 string commandText,
                 DataSet dataSet, string[] tableNames)
             {
                 FillDataset(transaction, commandType, commandText, dataSet, tableNames, null);
             }
 
             /// <summary>
             /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  FillDataset(trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             public static void FillDataset(SqlTransaction transaction, CommandType commandType,
                 string commandText, DataSet dataSet, string[] tableNames,
                 params SqlParameter[] commandParameters)
             {
                 FillDataset(transaction.Connection, transaction, commandType, commandText, dataSet, tableNames, commandParameters);
             }
 
             /// <summary>
             /// 执行指定数据库事务的命令,映射数据表并填充数据集,指定存储过程参数值.
             /// </summary>
             /// <remarks>
             /// 此方法不提供访问存储过程输出参数和返回值参数.
             ///
             /// 示例: 
             ///  FillDataset(trans, "GetOrders", ds, new string[]{"orders"}, 24, 36);
             /// </remarks>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>
             /// <param name="parameterValues">分配给存储过程输入参数的对象数组</param>
             public static void FillDataset(SqlTransaction transaction, string spName,
                 DataSet dataSet, string[] tableNames,
                 params object[] parameterValues)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (dataSet == null) throw new ArgumentNullException("dataSet");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果有参数值
                 if ((parameterValues != null) && (parameterValues.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 给存储过程参数赋值
                     AssignParameterValues(commandParameters, parameterValues);
 
                     // 调用重载方法
                     FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames, commandParameters);
                 }
                 else
                 {
                     // 没有参数值
                     FillDataset(transaction, CommandType.StoredProcedure, spName, dataSet, tableNames);
                 }
             }
 
             /// <summary>
             /// [私有方法][内部调用]执行指定数据库连接对象/事务的命令,映射数据表并填充数据集,DataSet/TableNames/SqlParameters.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  FillDataset(conn, trans, CommandType.StoredProcedure, "GetOrders", ds, new string[] {"orders"}, new SqlParameter("@prodid", 24));
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="transaction">一个有效的连接事务</param>
             /// <param name="commandType">命令类型 (存储过程,命令文本或其它)</param>
             /// <param name="commandText">存储过程名称或T-SQL语句</param>
             /// <param name="dataSet">要填充结果集的DataSet实例</param>
             /// <param name="tableNames">表映射的数据表数组
             /// 用户定义的表名 (可有是实际的表名.)
             /// </param>
             /// <param name="commandParameters">分配给命令的SqlParamter参数数组</param>
             private static void FillDataset(SqlConnection connection, SqlTransaction transaction, CommandType commandType,
                 string commandText, DataSet dataSet, string[] tableNames,
                 params SqlParameter[] commandParameters)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (dataSet == null) throw new ArgumentNullException("dataSet");
 
                 // 创建SqlCommand命令,并进行预处理
                 SqlCommand command = new SqlCommand();
                 bool mustCloseConnection = false;
                 PrepareCommand(command, connection, transaction, commandType, commandText, commandParameters, out mustCloseConnection);
 
                 // 执行命令
                 using (SqlDataAdapter dataAdapter = new SqlDataAdapter(command))
                 {
 
                     // 追加表映射
                     if (tableNames != null && tableNames.Length > 0)
                     {
                         string tableName = "Table";
                         for (int index = 0; index < tableNames.Length; index++)
                         {
                             if (tableNames[index] == null || tableNames[index].Length == 0) throw new ArgumentException("The tableNames parameter must contain a list of tables, a value was provided as null or empty string.", "tableNames");
                             dataAdapter.TableMappings.Add(tableName, tableNames[index]);
                             tableName += (index + 1).ToString();
                         }
                     }
 
                     // 填充数据集使用默认表名称
                     dataAdapter.Fill(dataSet);
 
                     // 清除参数,以便再次使用.
                     command.Parameters.Clear();
                 }
 
                 if (mustCloseConnection)
                     connection.Close();
             }
             #endregion
 
             #region UpdateDataset 更新数据集
             /// <summary>
             /// 执行数据集更新到数据库,指定inserted, updated, or deleted命令.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  UpdateDataset(conn, insertCommand, deleteCommand, updateCommand, dataSet, "Order");
             /// </remarks>
             /// <param name="insertCommand">[追加记录]一个有效的T-SQL语句或存储过程</param>
             /// <param name="deleteCommand">[删除记录]一个有效的T-SQL语句或存储过程</param>
             /// <param name="updateCommand">[更新记录]一个有效的T-SQL语句或存储过程</param>
             /// <param name="dataSet">要更新到数据库的DataSet</param>
             /// <param name="tableName">要更新到数据库的DataTable</param>
             public static void UpdateDataset(SqlCommand insertCommand, SqlCommand deleteCommand, SqlCommand updateCommand, DataSet dataSet, string tableName)
             {
                 if (insertCommand == null) throw new ArgumentNullException("insertCommand");
                 if (deleteCommand == null) throw new ArgumentNullException("deleteCommand");
                 if (updateCommand == null) throw new ArgumentNullException("updateCommand");
                 if (tableName == null || tableName.Length == 0) throw new ArgumentNullException("tableName");
 
                 // 创建SqlDataAdapter,当操作完成后释放.
                 using (SqlDataAdapter dataAdapter = new SqlDataAdapter())
                 {
                     // 设置数据适配器命令
                     dataAdapter.UpdateCommand = updateCommand;
                     dataAdapter.InsertCommand = insertCommand;
                     dataAdapter.DeleteCommand = deleteCommand;
 
                     // 更新数据集改变到数据库
                     dataAdapter.Update(dataSet, tableName);
 
                     // 提交所有改变到数据集.
                     dataSet.AcceptChanges();
                 }
             }
             #endregion
 
             #region CreateCommand 创建一条SqlCommand命令
             /// <summary>
             /// 创建SqlCommand命令,指定数据库连接对象,存储过程名和参数.
             /// </summary>
             /// <remarks>
             /// 示例: 
             ///  SqlCommand command = CreateCommand(conn, "AddCustomer", "CustomerID", "CustomerName");
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="sourceColumns">源表的列名称数组</param>
             /// <returns>返回SqlCommand命令</returns>
             public static SqlCommand CreateCommand(SqlConnection connection, string spName, params string[] sourceColumns)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 创建命令
                 SqlCommand cmd = new SqlCommand(spName, connection);
                 cmd.CommandType = CommandType.StoredProcedure;
 
                 // 如果有参数值
                 if ((sourceColumns != null) && (sourceColumns.Length > 0))
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 将源表的列到映射到DataSet命令中.
                     for (int index = 0; index < sourceColumns.Length; index++)
                         commandParameters[index].SourceColumn = sourceColumns[index];
 
                     // Attach the discovered parameters to the SqlCommand object
                     AttachParameters(cmd, commandParameters);
                 }
 
                 return cmd;
             }
             #endregion
 
             #region ExecuteNonQueryTypedParams 类型化参数(DataRow)
             /// <summary>
             /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回受影响的行数.
             /// </summary>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回影响的行数</returns>
             public static int ExecuteNonQueryTypedParams(String connectionString, String spName, DataRow dataRow)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回受影响的行数.
             /// </summary>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回影响的行数</returns>
             public static int ExecuteNonQueryTypedParams(SqlConnection connection, String spName, DataRow dataRow)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteNonQuery(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回受影响的行数.
             /// </summary>
             /// <param name="transaction">一个有效的连接事务 object</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回影响的行数</returns>
             public static int ExecuteNonQueryTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // Sf the row has values, the store procedure parameters must be initialized
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteNonQuery(transaction, CommandType.StoredProcedure, spName);
                 }
             }
             #endregion
 
             #region ExecuteDatasetTypedParams 类型化参数(DataRow)
             /// <summary>
             /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataSet.
             /// </summary>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回一个包含结果集的DataSet.</returns>
             public static DataSet ExecuteDatasetTypedParams(string connectionString, String spName, DataRow dataRow)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 //如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataSet.
             /// </summary>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回一个包含结果集的DataSet.</returns>
             ///
             public static DataSet ExecuteDatasetTypedParams(SqlConnection connection, String spName, DataRow dataRow)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteDataset(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回DataSet.
             /// </summary>
             /// <param name="transaction">一个有效的连接事务 object</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回一个包含结果集的DataSet.</returns>
             public static DataSet ExecuteDatasetTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteDataset(transaction, CommandType.StoredProcedure, spName);
                 }
             }
 
             #endregion
 
             #region ExecuteReaderTypedParams 类型化参数(DataRow)
             /// <summary>
             /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回DataReader.
             /// </summary>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReaderTypedParams(String connectionString, String spName, DataRow dataRow)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteReader(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
 
             /// <summary>
             /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回DataReader.
             /// </summary>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteReader(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库事物的存储过程,使用DataRow做为参数值,返回DataReader.
             /// </summary>
             /// <param name="transaction">一个有效的连接事务 object</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回包含结果集的SqlDataReader</returns>
             public static SqlDataReader ExecuteReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteReader(transaction, CommandType.StoredProcedure, spName);
                 }
             }
             #endregion
 
             #region ExecuteScalarTypedParams 类型化参数(DataRow)
             /// <summary>
             /// 执行指定连接数据库连接字符串的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
             /// </summary>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalarTypedParams(String connectionString, String spName, DataRow dataRow)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connectionString, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteScalar(connectionString, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
             /// </summary>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalarTypedParams(SqlConnection connection, String spName, DataRow dataRow)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteScalar(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回结果集中的第一行第一列.
             /// </summary>
             /// <param name="transaction">一个有效的连接事务 object</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回结果集中的第一行第一列</returns>
             public static object ExecuteScalarTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteScalar(transaction, CommandType.StoredProcedure, spName);
                 }
             }
             #endregion
 
             #region ExecuteXmlReaderTypedParams 类型化参数(DataRow)
             /// <summary>
             /// 执行指定连接数据库连接对象的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
             /// </summary>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回XmlReader结果集对象.</returns>
             public static XmlReader ExecuteXmlReaderTypedParams(SqlConnection connection, String spName, DataRow dataRow)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteXmlReader(connection, CommandType.StoredProcedure, spName);
                 }
             }
 
             /// <summary>
             /// 执行指定连接数据库事务的存储过程,使用DataRow做为参数值,返回XmlReader类型的结果集.
             /// </summary>
             /// <param name="transaction">一个有效的连接事务 object</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="dataRow">使用DataRow作为参数值</param>
             /// <returns>返回XmlReader结果集对象.</returns>
             public static XmlReader ExecuteXmlReaderTypedParams(SqlTransaction transaction, String spName, DataRow dataRow)
             {
                 if (transaction == null) throw new ArgumentNullException("transaction");
                 if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 // 如果row有值,存储过程必须初始化.
                 if (dataRow != null && dataRow.ItemArray.Length > 0)
                 {
                     // 从缓存中加载存储过程参数,如果缓存中不存在则从数据库中检索参数信息并加载到缓存中. ()
                     SqlParameter[] commandParameters = SqlHelperParameterCache.GetSpParameterSet(transaction.Connection, spName);
 
                     // 分配参数值
                     AssignParameterValues(commandParameters, dataRow);
 
                     return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName, commandParameters);
                 }
                 else
                 {
                     return SqlHelper.ExecuteXmlReader(transaction, CommandType.StoredProcedure, spName);
                 }
             }
             #endregion
 
         }
 
         /// <summary>
         /// SqlHelperParameterCache提供缓存存储过程参数,并能够在运行时从存储过程中探索参数.
         /// </summary>
         public sealed class SqlHelperParameterCache
         {
             #region 私有方法,字段,构造函数
             // 私有构造函数,妨止类被实例化.
             private SqlHelperParameterCache() { }
 
             // 这个方法要注意
             private static Hashtable paramCache = Hashtable.Synchronized(new Hashtable());
 
             /// <summary>
             /// 探索运行时的存储过程,返回SqlParameter参数数组.
             /// 初始化参数值为 DBNull.Value.
             /// </summary>
             /// <param name="connection">一个有效的数据库连接</param>
             /// <param name="spName">存储过程名称</param>
             /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
             /// <returns>返回SqlParameter参数数组</returns>
             private static SqlParameter[] DiscoverSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 SqlCommand cmd = new SqlCommand(spName, connection);
                 cmd.CommandType = CommandType.StoredProcedure;
 
                 connection.Open();
                 // 检索cmd指定的存储过程的参数信息,并填充到cmd的Parameters参数集中.
                 SqlCommandBuilder.DeriveParameters(cmd);
                 connection.Close();
                 // 如果不包含返回值参数,将参数集中的每一个参数删除.
                 if (!includeReturnValueParameter)
                 {
                     cmd.Parameters.RemoveAt(0);
                 }
 
                 // 创建参数数组
                 SqlParameter[] discoveredParameters = new SqlParameter[cmd.Parameters.Count];
                 // 将cmd的Parameters参数集复制到discoveredParameters数组.
                 cmd.Parameters.CopyTo(discoveredParameters, 0);
 
                 // 初始化参数值为 DBNull.Value.
                 foreach (SqlParameter discoveredParameter in discoveredParameters)
                 {
                     discoveredParameter.Value = DBNull.Value;
                 }
                 return discoveredParameters;
             }
 
             /// <summary>
             /// SqlParameter参数数组的深层拷贝.
             /// </summary>
             /// <param name="originalParameters">原始参数数组</param>
             /// <returns>返回一个同样的参数数组</returns>
             private static SqlParameter[] CloneParameters(SqlParameter[] originalParameters)
             {
                 SqlParameter[] clonedParameters = new SqlParameter[originalParameters.Length];
 
                 for (int i = 0, j = originalParameters.Length; i < j; i++)
                 {
                     clonedParameters[i] = (SqlParameter)((ICloneable)originalParameters[i]).Clone();
                 }
 
                 return clonedParameters;
             }
 
             #endregion 私有方法,字段,构造函数结束
 
             #region 缓存方法
 
             /// <summary>
             /// 追加参数数组到缓存.
             /// </summary>
             /// <param name="connectionString">一个有效的数据库连接字符串</param>
             /// <param name="commandText">存储过程名或SQL语句</param>
             /// <param name="commandParameters">要缓存的参数数组</param>
             public static void CacheParameterSet(string connectionString, string commandText, params SqlParameter[] commandParameters)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");
 
                 string hashKey = connectionString + ":" + commandText;
 
                 paramCache[hashKey] = commandParameters;
             }
 
             /// <summary>
             /// 从缓存中获取参数数组.
             /// </summary>
             /// <param name="connectionString">一个有效的数据库连接字符</param>
             /// <param name="commandText">存储过程名或SQL语句</param>
             /// <returns>参数数组</returns>
             public static SqlParameter[] GetCachedParameterSet(string connectionString, string commandText)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (commandText == null || commandText.Length == 0) throw new ArgumentNullException("commandText");
 
                 string hashKey = connectionString + ":" + commandText;
 
                 SqlParameter[] cachedParameters = paramCache[hashKey] as SqlParameter[];
                 if (cachedParameters == null)
                 {
                     return null;
                 }
                 else
                 {
                     return CloneParameters(cachedParameters);
                 }
             }
 
             #endregion 缓存方法结束
 
             #region 检索指定的存储过程的参数集
 
             /// <summary>
             /// 返回指定的存储过程的参数集
             /// </summary>
             /// <remarks>
             /// 这个方法将查询数据库,并将信息存储到缓存.
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符</param>
             /// <param name="spName">存储过程名</param>
             /// <returns>返回SqlParameter参数数组</returns>
             public static SqlParameter[] GetSpParameterSet(string connectionString, string spName)
             {
                 return GetSpParameterSet(connectionString, spName, false);
             }
 
             /// <summary>
             /// 返回指定的存储过程的参数集
             /// </summary>
             /// <remarks>
             /// 这个方法将查询数据库,并将信息存储到缓存.
             /// </remarks>
             /// <param name="connectionString">一个有效的数据库连接字符.</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
             /// <returns>返回SqlParameter参数数组</returns>
             public static SqlParameter[] GetSpParameterSet(string connectionString, string spName, bool includeReturnValueParameter)
             {
                 if (connectionString == null || connectionString.Length == 0) throw new ArgumentNullException("connectionString");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 using (SqlConnection connection = new SqlConnection(connectionString))
                 {
                     return GetSpParameterSetInternal(connection, spName, includeReturnValueParameter);
                 }
             }
 
             /// <summary>
             /// [内部]返回指定的存储过程的参数集(使用连接对象).
             /// </summary>
             /// <remarks>
             /// 这个方法将查询数据库,并将信息存储到缓存.
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接字符</param>
             /// <param name="spName">存储过程名</param>
             /// <returns>返回SqlParameter参数数组</returns>
             internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName)
             {
                 return GetSpParameterSet(connection, spName, false);
             }
 
             /// <summary>
             /// [内部]返回指定的存储过程的参数集(使用连接对象)
             /// </summary>
             /// <remarks>
             /// 这个方法将查询数据库,并将信息存储到缓存.
             /// </remarks>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="includeReturnValueParameter">
             /// 是否包含返回值参数
             /// </param>
             /// <returns>返回SqlParameter参数数组</returns>
             internal static SqlParameter[] GetSpParameterSet(SqlConnection connection, string spName, bool includeReturnValueParameter)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 using (SqlConnection clonedConnection = (SqlConnection)((ICloneable)connection).Clone())
                 {
                     return GetSpParameterSetInternal(clonedConnection, spName, includeReturnValueParameter);
                 }
             }
 
             /// <summary>
             /// [私有]返回指定的存储过程的参数集(使用连接对象)
             /// </summary>
             /// <param name="connection">一个有效的数据库连接对象</param>
             /// <param name="spName">存储过程名</param>
             /// <param name="includeReturnValueParameter">是否包含返回值参数</param>
             /// <returns>返回SqlParameter参数数组</returns>
             private static SqlParameter[] GetSpParameterSetInternal(SqlConnection connection, string spName, bool includeReturnValueParameter)
             {
                 if (connection == null) throw new ArgumentNullException("connection");
                 if (spName == null || spName.Length == 0) throw new ArgumentNullException("spName");
 
                 string hashKey = connection.ConnectionString + ":" + spName + (includeReturnValueParameter ? ":include ReturnValue Parameter" : "");
 
                 SqlParameter[] cachedParameters;
 
                 cachedParameters = paramCache[hashKey] as SqlParameter[];
                 if (cachedParameters == null)
                 {
                     SqlParameter[] spParameters = DiscoverSpParameterSet(connection, spName, includeReturnValueParameter);
                     paramCache[hashKey] = spParameters;
                     cachedParameters = spParameters;
                 }
 
                 return CloneParameters(cachedParameters);
             }
 
             #endregion 参数集检索结束
 
         }
 
     }
时间: 2024-10-28 01:51:57

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