1using System;
 2using System.Data;
 3using System.Collections;
 4using System.Drawing;
 5
 6public partial class getCode : System.Web.UI.Page
 7...{
 8    protected void Page_Load(object sender, EventArgs e)
 9    ...{
10        this.CreateCheckCodeImage(GenerateCheckCode());
11    }
12
13    private string GenerateCheckCode()
14    ...{
15        int number;
16        char code;
17        string checkCode = String.Empty;
18
19        System.Random random = new Random();
20
21        for (int i = 0; i < 4; i++)
22        ...{
23            number = random.Next();
24
25            // if (number % 2 == 0)
26                code = (char)('0' + (char)(number % 10));
27            // else
28            //    code = (char)('A' + (char)(number % 26));
29
30            checkCode += code.ToString();
31        }
32
33        //Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
34        Session["CheckCode"] = checkCode;
35
36        return checkCode;
37    }
38
39    private void CreateCheckCodeImage(string checkCode)
40    ...{
41        if (checkCode == null || checkCode.Trim() == String.Empty)
42            return;
43
44        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 13.5)), 22);
45        Graphics g = Graphics.FromImage(image);
46
47        try
48        ...{
49            //生成随机生成器
50            Random random = new Random();
51
52            //清空图片背景色
53            g.Clear(Color.White);
54
55            //画图片的背景噪音线
56            for (int i = 0; i < 10; i++)
57            ...{
58                int x1 = random.Next(image.Width);
59                int x2 = random.Next(image.Width);
60                int y1 = random.Next(image.Height);
61                int y2 = random.Next(image.Height);
62
63                g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
64            }
65
66            Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
67            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
68            g.DrawString(checkCode, font, brush, 2, 2);
69
70            //画图片的前景噪音点
71            for (int i = 0; i < 10; i++)
72            ...{
73                int x = random.Next(image.Width);
74                int y = random.Next(image.Height);
75
76                image.SetPixel(x, y, Color.FromArgb(random.Next()));
77            }
78
79            //画图片的边框线
80            g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
81
82            System.IO.MemoryStream ms = new System.IO.MemoryStream();
83            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
84
85            //history back 不重复
86            Response.Cache.SetNoStore();
87            Response.ClearContent();
88            Response.ContentType = "image/Gif";
89            Response.BinaryWrite(ms.ToArray());
90        }
91        finally
92        ...{
93            g.Dispose();
94            image.Dispose();
95        }
96    }
97}
98