1using System;
 2using System.Data;
 3using System.Configuration;
 4using System.Collections;
 5using System.Web;
 6using System.Web.Security;
 7using System.Web.UI;
 8using System.Web.UI.WebControls;
 9using System.Web.UI.WebControls.WebParts;
10using System.Web.UI.HtmlControls;
11using System.Drawing;
12using System.Text;
13using System.Drawing.Drawing2D;
14using System.Drawing.Imaging;
15
16public partial class Manager_CheckImage : System.Web.UI.Page
17...{
18    protected void Page_Load(object sender, EventArgs e)
19    ...{
20        CheckImage(GetCode(5));
21    }
22    //返回验证码的位数
23    protected string GetCode(int i) ...{
24
25        Random ran = new Random();
26        string strCode = string.Empty;
27        string[] str =...{ "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", "v", "w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };
28        for (int j = 0; j < i; j++) ...{
29
30            strCode += str[ran.Next(str.Length)];
31        
32        }
33        Session["CheckCode"] = strCode;
34        return strCode;
35        
36    }
37    protected void CheckImage(string nCode) ...{
38
39        Random ran=new Random();
40        Bitmap img = new Bitmap(70, 24);
41        Graphics g = Graphics.FromImage(img);
42        g.Clear(System.Drawing.Color.White);
43        for (int i = 0; i < 30; i++) ...{
44
45            g.DrawLine(Pens.Gainsboro, new Point(ran.Next(img.Width), ran.Next(img.Height)), new Point(ran.Next(img.Height),ran.Next(img.Width)));
46        
47        }
48        g.DrawRectangle(Pens.Green, new Rectangle(0, 0, 69, 23));
49        Font font = new Font("Arail", 12, FontStyle.Bold);
50        g.DrawString(nCode, font, Brushes.Black, new Point(5, 4));
51        System.IO.MemoryStream ms = new System.IO.MemoryStream();
52        img.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
53        Response.ClearContent();
54        Response.ContentType = "Image/Gif";
55        Response.BinaryWrite(ms.ToArray());
56    
57    }
58}
59