C#生成简单验证码的代码
html页面
- <!--
- Document : ASP.NET用一般处理程序生成验证码
- Created on : 2008-10-13 17:04
- Author : 牛腩
- -->
- <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
- <html>
- <head>
- <title></title>
- <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
- <script type="text/javascript">
- function change() {
- var imgNode = document.getElementById("vimg");
- imgNode.src = "WaterMark.ashx?t=" + (new Date()).valueOf(); // 这里加个时间的参数是为了防止浏览器缓存的问题
- }
- </script>
- </head>
- <body>
- <img src1="WaterMark.ashx" id="vimg" alt="" /><input type="button" value="换一张图片" onclick="change()" />
- </body>
- </html>
- //一般处理程序WaterMark.ashx的代码
- <%@ 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));
- 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);
- g.DrawString(checkCode, font, brush, 2, 2);
- //画图片的前景噪音点
- g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
- System.IO.MemoryStream ms = new System.IO.MemoryStream();
- image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
- context.Response.ClearContent();
- context.Response.ContentType = "image/Gif";
- context.Response.BinaryWrite(ms.ToArray());
- }
- finally
- {
- g.Dispose();
- image.Dispose();
- }
- }
- /// <summary>
- /// 产生随机字符串
- /// </summary>
- /// <param name="num">随机出几个字符</param>
- /// <returns>随机出的字符串</returns>
- private string GenCode(int num)
- {
- string str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
- char[] chastr = str.ToCharArray();
- // string[] source ={ "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", "#", "$", "%", "&", "@" };
- string code = "";
- Random rd = new Random();
- int i;
- for (i = 0; i < num; i++)
- {
- //code += source[rd.Next(0, source.Length)];
- code += str.Substring(rd.Next(0, str.Length), 1);
- }
- return code;
- }
- public bool IsReusable
- {
- get
- {
- return false;
- }
- }
- }
来源: http://www.phpxs.com/code/1004604/