下面是ＧＤＩ＋绘图的代码段，以及显示的调用等
using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Drawing.Drawing2D;using System.Drawing.Imaging;using System.Drawing.Text;using System.Drawing;using System.Text; public partial class png : System.Web.UI.Page{ private readonly string ImagePath = "Validator.jpg"; private static string gif = ""; protected void Page_Load(object sender, EventArgs e) { switch (Request.QueryString["aa"]) { case "1": gif = stxt(); Session["gif"]= stxt(); break; case "2": gif = GetRandomint(); Session["gif"]= GetRandomint(); break; case "3": gif = RndNum(3); Session["gif"]= RndNum(3); break; default: gif = RndNum(3); Session["gif"]= GetRandomint(); break; } /**////创建Bmp位图 Bitmap bitMapImage = new System.Drawing.Bitmap(Server.MapPath(ImagePath)); Graphics graphicImage = Graphics.FromImage(bitMapImage); /**////设置画笔的输出模式 graphicImage.SmoothingMode = SmoothingMode.HighSpeed; /**////添加文本字符串 graphicImage.DrawString(gif, new Font("Arial", 20, FontStyle.Bold), SystemBrushes.WindowText, new Point(0, 0)); /**////设置图像输出的格式 Response.ContentType = "image/jpeg"; /**////保存数据流 bitMapImage.Save(Response.OutputStream, ImageFormat.Jpeg); /**////释放占用的资源 graphicImage.Dispose(); bitMapImage.Dispose(); }
返回纯数字
private String GetRandomint() { Random random = new Random(); return (random.Next(100000, 999999).ToString()); }
返回文字＼数字＼字母混合的
public static String RndNum(int VcodeNum) { String Vchar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,W,X,Y,Z,呵,哈,弹,簧,秤,嬉,戏"; String[] VcArray = Vchar.Split(','); String VNum = ""; Random random = new Random(); for (int i = 1; i <= VcodeNum; i++) { int iNum = 0; while ((iNum = Convert.ToInt32(VcArray.Length * random.NextDouble())) ==VcArray.Length ) { iNum = Convert.ToInt32(VcArray.Length * random.NextDouble()); } VNum += VcArray[iNum]; // VNum += VcArray[Convert.ToInt32(VcArray.Length*random.NextDouble())]; } return VNum; }
返回汉字的
public static object[] CreateRegionCode(int strlength) { //定义一个字符串数组储存汉字编码的组成元素 string[] rBase=new String [16]{"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"}; Random rnd=new Random(); //定义一个object数组用来 object[] bytes=new object[strlength]; /**//**//**//*每循环一次产生一个含两个元素的十六进制字节数组，并将其放入bject数组中 每个汉字有四个区位码组成 区位码第1位和区位码第2位作为字节数组第一个元素 区位码第3位和区位码第4位作为字节数组第二个元素 */ for(int i=0;i<strlength;i++) { //区位码第1位 int r1=rnd.Next(11,14); string str_r1=rBase[r1].Trim(); //区位码第2位 rnd=new Random(r1*unchecked((int)DateTime.Now.Ticks)+i);//更换随机数发生器的种子避免产生重复值 int r2; if (r1==13) { r2=rnd.Next(0,7); } else { r2=rnd.Next(0,16); } string str_r2=rBase[r2].Trim(); //区位码第3位 rnd=new Random(r2*unchecked((int)DateTime.Now.Ticks)+i); int r3=rnd.Next(10,16); string str_r3=rBase[r3].Trim(); //区位码第4位 rnd=new Random(r3*unchecked((int)DateTime.Now.Ticks)+i); int r4; if (r3==10) { r4=rnd.Next(1,16); } else if (r3==15) { r4=rnd.Next(0,15); } else { r4=rnd.Next(0,16); } string str_r4=rBase[r4].Trim(); //定义两个字节变量存储产生的随机汉字区位码 byte byte1=Convert.ToByte(str_r1 + str_r2,16); byte byte2=Convert.ToByte(str_r3 + str_r4,16); //将两个字节变量存储在字节数组中 byte[] str_r=new byte[]{byte1,byte2}; //将产生的一个汉字的字节数组放入object数组中 bytes.SetValue(str_r,i); } return bytes; } private string stxt() { Encoding gb = Encoding.GetEncoding("gb2312"); //调用函数产生4个随机中文汉字编码 object[] bytes = CreateRegionCode(3); //根据汉字编码的字节数组解码出中文汉字 string str1 = gb.GetString((byte[])Convert.ChangeType(bytes[0], typeof(byte[]))); string str2 = gb.GetString((byte[])Convert.ChangeType(bytes[1], typeof(byte[]))); string str3 = gb.GetString((byte[])Convert.ChangeType(bytes[2], typeof(byte[]))); string txt = str1 + str2 + str3; return txt; }
我们调用页的代码如下
ＨＴＭＬ代码
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="view.aspx.cs" Inherits="view" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>无标题页</title></head><body> <form id="form1" runat="server"> <div> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <asp:Image ID="Image1" runat="server" ImageUrl="png.aspx" /><br /> <br /> <asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="Button" /> <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged"> <asp:ListItem Value="3">默认</asp:ListItem> <asp:ListItem Value="1">文字</asp:ListItem> <asp:ListItem Value="2">数字</asp:ListItem> <asp:ListItem Value="3">混合</asp:ListItem> </asp:DropDownList></div> </form></body></html>
ＣＳ代码
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { switch (DropDownList1.SelectedValue) { case "1": Image1.ImageUrl = "png.aspx?aa=1"; break; case "2": Image1.ImageUrl = "png.aspx?aa=2"; break; case "3": Image1.ImageUrl = "png.aspx?aa=3"; break; } } protected void Button2_Click(object sender, EventArgs e) { if (TextBox1.Text == Session["gif"].ToString()) Response.Write("OK,正确"); else Response.Write("验证码不符合"); }