1: vs2005 + ajax + Access 开发 2: 格式简洁

				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;
				public partial class VerifyCode : System.Web.UI.Page
				{
				    protected void Page_Load(object sender, System.EventArgs e)
				    {
				        Session["VerifyCode"] = MakeValidateCode();
				        CreateImage(Session["VerifyCode"].ToString());
				    }
				    private void CreateImage(string checkCode)
				    {
				        int iwidth = (int)(checkCode.Length * 12) + 10;
				        System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 25);
				        Graphics g = Graphics.FromImage(image);
				        g.Clear(Color.White);
				        //定义颜色
				        Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
				        //定义字体
				        string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };
				        Random rand = new Random();
				        //随机输出噪点
				        for (int i = 0; i < 5; i++)
				        {
				            int x = rand.Next(image.Width);
				            int y = rand.Next(image.Height);
				            g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1);
				        }
				
				        //输出不同字体和颜色的验证码字符
				        for (int i = 0; i < checkCode.Length; i++)
				        {
				            int cindex = rand.Next(7);
				            int findex = rand.Next(5);
				
				            Font f = new System.Drawing.Font("宋体", 12, System.Drawing.FontStyle.Regular);
				            Brush b = new System.Drawing.SolidBrush(c[cindex]);
				            int ii = 4;
				            if ((i + 1) % 2 == 0)
				            {
				                ii = 2;
				            }
				            g.DrawString(checkCode.Substring(i, 1), f, b, 3 + (i * 12), ii);
				        }
				        //画一个边框
				        g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);
				
				        //输出到浏览器
				        System.IO.MemoryStream ms = new System.IO.MemoryStream();
				        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
				        Response.ClearContent();
				        Response.ContentType = "image/Jpeg";
				        Response.BinaryWrite(ms.ToArray());
				        g.Dispose();
				        image.Dispose();
				    }
				
				
				    private string MakeValidateCode()
				    {
				        //0 i o
				        char[] s = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
				        string num = "";
				        Random r = new Random();
				        for (int i = 0; i < 4; i++)
				        {
				            num += s[r.Next(0, s.Length - 1)].ToString();
				        }
				        return num;
				    }
				
				}