c#利用反射，实现将model类变成字符串、再还原成mode对象的功能

public string ToString(UserGiftCardModel model)
        {
            if (model == null) return "";
            string sb = "";
            Type type =model.GetType() ;//assembly.GetType("Reflect_test.PurchaseOrderHeadManageModel", true, true); //命名空间名称 + 类名  

            //创建类的实例
            //object obj = Activator.CreateInstance(type, true);

            //获取公共属性
            PropertyInfo[] Propertys = type.GetProperties();
            for (int i = 0; i < Propertys.Length; i++)
            {
                // Propertys[i].SetValue(Propertys[i], i, null); //设置值
                PropertyInfo pi = type.GetProperty(Propertys[i].Name);
                object val=pi.GetValue(model, null);
                string value = val == null ? "" : val.ToString(); ;
                sb += Propertys[i].Name +"|"+ value + "_"; //获取值
               // Console.WriteLine("属性名：{0},类型：{1}", Propertys[i].Name, Propertys[i].PropertyType);
            }

            if(sb.Length>0) sb=sb.Substring(0,sb.Length-1);
            return sb;
        }
        public UserGiftCardModel DesToString(string modelstr)
        {
            if (modelstr == "") return null;
            UserGiftCardModel model = new UserGiftCardModel();
            Type type = model.GetType();//assembly.GetType("Reflect_test.PurchaseOrderHeadManageModel", true, true); //命名空间名称 + 类名  

            //创建类的实例
            //object obj = Activator.CreateInstance(type, true);

            Dictionary<string, object> dict = new Dictionary<string, object>();

            //获取公共属性
            PropertyInfo[] Propertys = type.GetProperties();
            object[] objs = modelstr.Split('_');
            foreach (object obj in objs)
            {
                object[] obj1 = obj.ToString().Split('|');
                dict[obj1[0].ToString()] = obj1[1];
            }
            for (int i = 0; i < Propertys.Length; i++)
            {
               string p_type= Propertys[i].PropertyType.ToString().ToLower();
               if (dict[Propertys[i].Name].ToString() == "") dict[Propertys[i].Name] = null;
                // Propertys[i].SetValue(Propertys[i], i, null); //设置值
               PropertyInfo pi = type.GetProperty(Propertys[i].Name);
                object value=null;
                if (p_type.Contains("decimal"))
                {
                    if (dict[Propertys[i].Name] != null)
                        value = Convert.ToDecimal(dict[Propertys[i].Name]);
                }
                else if (p_type.Contains("int32"))
                {
                    if (dict[Propertys[i].Name] != null)
                        value = Convert.ToInt32(dict[Propertys[i].Name]);
                }
                else if (p_type.Contains("int64"))
                {
                    if (dict[Propertys[i].Name] != null)
                        value = Convert.ToInt64(dict[Propertys[i].Name]);
                }
                else if (p_type.Contains("datetime") || p_type.Contains("date"))
                {
                    if (dict[Propertys[i].Name] != null)
                        value = Convert.ToDateTime(dict[Propertys[i].Name]);
                }
                else
                {
                    value = dict[Propertys[i].Name];
                }
                pi.SetValue(model, value, null);

                //Console.WriteLine("属性名：{0},类型：{1}", Propertys[i].Name, Propertys[i].PropertyType);
            }

            return model;
        }

	public class UserGiftCardModel
	{
		#region 构造函数
		/// <summary>
		/// 无参构造函数
		/// </summary>
		public UserGiftCardModel(){}
		/// <summary>
        /// 有参构造函数
        /// </summary>
		/// <param name=" _cardnumber">礼品卡号</param>
		/// <param name=" _password">卡密码</param>
		/// <param name=" _festivalname">节日名称</param>
		/// <param name=" _facevalue">面值</param>
		/// <param name=" _balance">余额</param>
		/// <param name=" _couponamount">奖励金额</param>
		/// <param name=" _picture">图片</param>
		/// <param name=" _title">标题 </param>
		/// <param name=" _buytime">购买时间</param>
		/// <param name=" _buyid">购买人ID</param>
		/// <param name=" _recieveid">接收人ID</param>
		/// <param name=" _receiveemail">接收者邮箱</param>
		/// <param name=" _leavewords">留言</param>
		public UserGiftCardModel(string _cardnumber,string _password,string _festivalname,decimal _facevalue,decimal _balance,decimal _couponamount,string _picture,string _title,DateTime _buytime,int _buyid,int _recieveid,string _receiveemail,string _leavewords)
        {
	        this._cardnumber = _cardnumber;
	        this._password = _password;
	        this._festivalname = _festivalname;
	        this._facevalue = _facevalue;
	        this._balance = _balance;
	        this._couponamount = _couponamount;
	        this._picture = _picture;
	        this._title = _title;
	        this._buytime = _buytime;
	        this._buyid = _buyid;
	        this._recieveid = _recieveid;
	        this._receiveemail = _receiveemail;
	        this._leavewords = _leavewords;
        }
        #endregion

		#region 数据库字段对应的属性
      	private string _cardnumber = "";
		/// <summary>
		/// 礼品卡号
        /// </summary>
        public string CardNumber
        {
            get{ return _cardnumber; }
            set{ _cardnumber = value; }
        }
        private string _password = "";
		/// <summary>
		/// 卡密码
        /// </summary>
        public string Password
        {
            get{ return _password; }
            set{ _password = value; }
        }
        private string _festivalname = "";
		/// <summary>
		/// 节日名称
        /// </summary>
        public string FestivalName
        {
            get{ return _festivalname; }
            set{ _festivalname = value; }
        }
        private decimal? _facevalue = null;
		/// <summary>
		/// 面值
        /// </summary>
        public decimal? FaceValue
        {
            get{ return _facevalue; }
            set{ _facevalue = value; }
        }
        private decimal? _balance = null;
		/// <summary>
		/// 余额
        /// </summary>
        public decimal? Balance
        {
            get{ return _balance; }
            set{ _balance = value; }
        }
        private decimal? _couponamount = null;
		/// <summary>
		/// 奖励金额
        /// </summary>
        public decimal? CouponAmount
        {
            get{ return _couponamount; }
            set{ _couponamount = value; }
        }
        private string _picture = "";
		/// <summary>
		/// 图片
        /// </summary>
        public string Picture
        {
            get{ return _picture; }
            set{ _picture = value; }
        }
        private string _title = "";
		/// <summary>
		/// 标题
        /// </summary>
        public string Title
        {
            get{ return _title; }
            set{ _title = value; }
        }
        private DateTime? _buytime = null;
		/// <summary>
		/// 购买时间
        /// </summary>
        public DateTime? BuyTime
        {
            get{ return _buytime; }
            set{ _buytime = value; }
        }
        private int? _buyid = null;
		/// <summary>
		/// 购买人ID
        /// </summary>
        public int? BuyID
        {
            get{ return _buyid; }
            set{ _buyid = value; }
        }
        private int? _recieveid = null;
		/// <summary>
		/// 接收人ID
        /// </summary>
        public int? RecieveID
        {
            get{ return _recieveid; }
            set{ _recieveid = value; }
        }
        private string _receiveemail = "";
		/// <summary>
		/// 接收者邮箱
        /// </summary>
        public string ReceiveEmail
        {
            get{ return _receiveemail; }
            set{ _receiveemail = value; }
        }
        private string _leavewords = "";
		/// <summary>
		/// 留言
        /// </summary>
        public string LeaveWords
        {
            get{ return _leavewords; }
            set{ _leavewords = value; }
        }
        #endregion

        #region 根据需要自定义字段
        //private string _test = "";
        ///// <summary>
        ///// 其他字段
        ///// </summary>
        //public string Test
        //{
        //    get { return _test; }
        //    set { _test = value; }
        //}
        #endregion

	}

已测试过。