.NET使用一般处理程序生成验证码(2)

一般处理程序WaterMark.ashx的代码:

[csharp]
<%@ WebHandler Language="C#" Class="WaterMark" %> 
 
using System; 
using System.Web; 
using System.Drawing; 
using System.Drawing.Drawing2D; 
using System.Web.SessionState;   
 
public class WaterMark : IHttpHandler, IRequiresSessionState  // 要使用session必须实现该接口,记得要导入System.Web.SessionState命名空间  
{ 
 
    public void ProcessRequest(HttpContext context) 
    { 
        string checkCode = GenCode(5);  // 产生5位随机字符  
        context.Session["Code"] = checkCode; //将字符串保存到Session中，以便需要时进行验证  
        System.Drawing.Bitmap image = new System.Drawing.Bitmap(70, 22); 
        Graphics g = Graphics.FromImage(image); 
        try 
        { 
            //生成随机生成器  
            Random random = new Random(); 
 
            //清空图片背景色  
            g.Clear(Color.White); 
 
            // 画图片的背景噪音线  
            int i; 
            for (i = 0; i < 25; i++) 
            { 
                int x1 = random.Next(image.Width); 
                int x2 = random.Next(image.Width); 
                int y1 = random.Next(image.Height); 
                int y2 = random.Next(image.Height); 
                g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2); 
            } 
 
            Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));