原文发布时间为：2008-09-22 —— 来源于本人的百度文章 [由搬家工具导入]
参考资料：http://www.cnblogs.com/gwazy/articles/139510.html
三个窗体：
default1:
属性值：
源码：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!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:ImageButton ID="ImageButton1" runat="server" CausesValidation="False" Height="35px"
ImageUrl="~/Default2.aspx" ToolTip="看不清图片？点击更换" Width="75px" /><br />
<br />
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" /></div>
</form>
</body>
</html>
代码：
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
if (string.Compare(TextBox1.Text, Session["checkcode"].ToString(),true)==0)
{
Response.Redirect("~/Default3.aspx");
}
}
}
default2为空窗体：
代码：
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;
using System.Drawing.Design;
using System.IO;
public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
System.Random rd = new Random();
int number;
char code;
string checkcode=string.Empty;
for (int i = 0; i < 4; i++)
{
number = rd.Next();
if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else
code = (char)('A' + (char)(number % 26));
checkcode += code.ToString();
}
Session["checkcode"] = checkcode;
Bitmap bp = new Bitmap(75, 35);
Graphics g = Graphics.FromImage(bp);
g.Clear(Color.White);
for (int i = 0; i < 40; i++)
{
int x1 = rd.Next(bp.Width);
int y1 = rd.Next(bp.Height);
int x2 = rd.Next(bp.Width);
int y2 = rd.Next(bp.Height);
g.DrawLine(new Pen(Color.Aqua), x1, y1, x2, y2);
}
Font ft = new Font("Arial", 18, FontStyle.Bold | FontStyle.Italic);
System.Drawing.Drawing2D.LinearGradientBrush lgb = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, bp.Width, bp.Height), Color.Blue, Color.Blue,10, true);
g.DrawString(checkcode, ft, lgb, 2, 2);
for (int i = 0; i < 80; i++)
{
int x = rd.Next(bp.Width);
int y = rd.Next(bp.Height);
bp.SetPixel(x, y, Color.FromArgb(rd.Next()));
}
g.DrawRectangle(new Pen(Color.Silver), 0, 0, bp.Width-1 , bp.Height-1 );
MemoryStream ms = new MemoryStream();
bp.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
//Response.ClearContent();
//Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
g.Dispose();
ms.Dispose();
ms.Close();
}
}
default3为空窗体（MD5值的使用）：
代码：
public partial class Default3 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
string md5= System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(Session["checkcode"].ToString(),"MD5");
Response.Write(md5);
}
}