随机验证码 

  1 using System;
  2 using System.Collections;
  3 using System.ComponentModel;
  4 using System.Data;
  5 using System.Drawing;
  6 using System.Web;
  7 using System.Web.SessionState;
  8 using System.Web.UI;
  9 using System.Web.UI.WebControls;
 10 using System.Web.UI.HtmlControls;
 11 
 12 namespace tenfu_OA
 13 {
 14     /// <summary>
 15     /// imgcode 的摘要说明。
 16     /// </summary>
 17     public partial class imgcode : System.Web.UI.Page
 18     {
 19         protected void Page_Load(object sender, System.EventArgs e)
 20         {
 21             // 在此处放置用户代码以初始化页面
 22             string checkcode=GenerateCheckCode();
 23             CreateCheckCodeImage(checkcode);
 24         }
 25 
 26         #region Web 窗体设计器生成的代码
 27         override protected void OnInit(EventArgs e)
 28         {
 29             //
 30             // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
 31             //
 32             InitializeComponent();
 33             base.OnInit(e);
 34         }
 35         
 36         /// <summary>
 37         /// 设计器支持所需的方法 - 不要使用代码编辑器修改
 38         /// 此方法的内容。
 39         /// </summary>
 40         private void InitializeComponent()
 41         {    
 42         }
 43         #endregion
 44 
 45         private string GenerateCheckCode()
 46         {  //产生五位的随机字符串
 47             int number;
 48             char code;
 49             string checkCode = String.Empty;
 50 
 51             System.Random random = new Random();
 52 
 53             for (int i = 0; i < 5; i++)
 54             {
 55                 number = random.Next();
 56 
 57                 //if (number % 2 == 0)
 58                     code = (char)('0' + (char)(number % 10));
 59                 //else
 60                     //code = (char)('A' + (char)(number % 26));
 61 
 62                 checkCode += code.ToString();
 63             }
 64 
 65             //Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
 66             Session["checkcode"] = checkCode;//用于客户端校验码比较
 67 
 68             return checkCode;
 69         }
 70 
 71         private void CreateCheckCodeImage(string checkCode)
 72         {  //将验证码生成图片显示
 73             if (checkCode == null || checkCode.Trim() == String.Empty)
 74                 return;
 75             //System.Drawing.Bitmap image2 = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
 76             System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
 77             Graphics g = Graphics.FromImage(image);
 78             //g.DrawImage(image2,0,0);
 79             try
 80             {
 81                 //生成随机生成器 
 82                 Random random = new Random();
 83 
 84                 //清空图片背景色 
 85                 g.Clear(Color.White);
 86 
 87                 //画图片的背景噪音线 
 88                                 for (int i = 0; i < 25; i++)
 89                                 {
 90                                     int x1 = random.Next(image.Width);
 91                                     int x2 = random.Next(image.Width);
 92                                     int y1 = random.Next(image.Height);
 93                                     int y2 = random.Next(image.Height);
 94                 
 95                                     g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
 96                                 }
 97 
 98                 Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
 99                 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);
100                 g.DrawString(checkCode, font, brush, 2, 2);
101 
102                 //画图片的前景噪音点 
103 //                                for (int i = 0; i < 100; i++)
104 //                                {
105 //                                    int x = random.Next(image.Width);
106 //                                    int y = random.Next(image.Height);
107 //                
108 //                                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
109 //                                }
110 
111                 //画图片的边框线 
112                 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
113 
114                 System.IO.MemoryStream ms = new System.IO.MemoryStream();
115                 image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
116                 Response.ClearContent();
117                 Response.ContentType = "image/Gif";
118                 Response.BinaryWrite(ms.ToArray());
119                 ms.Close();
120             }
121             finally
122             {
123                 g.Dispose();
124                 image.Dispose();
125             }
126         }
127     }
128 }
posted @ 2011-04-01 10:24  xfyn  阅读(273)  评论(0)    收藏  举报