1、新建CheckCodeImageExt.aspx
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Drawing; namespace CheckCode { public partial class CheckCodeImageExt : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { CreateCheckCodeImage(GenarateCheckCode()); } private string GenarateCheckCode() { int number; char code; string CheckCode = string.Empty; System.Random random = new Random(); for (int i = 0; i < 5; i++) { number = random.Next(); if (number % 2 == 0) code = (char)('0' + (char)(number % 10)); else code = (char)('A' + (char)(number % 26)); CheckCode += code.ToString(); } Session["CheckCode"] = CheckCode; return CheckCode; } private void CreateCheckCodeImage(string checkCode) { if (checkCode == null || checkCode.Trim() == string.Empty) return; System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling(checkCode.Length * 12.5), 24);//宽度，高度 Graphics g = Graphics.FromImage(image); try { Random random = new Random(); //清空图片背景色，并用白色填充 g.Clear(Color.White); //画图片的背景噪音线 for (int 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.FontStyle.Italic)); 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 for (int i = 0; i < 100; i++) { int x = random.Next(image.Width); int y = random.Next(image.Height); image.SetPixel(x, y, Color.FromArgb(random.Next())); } //画图片的边框线 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); Response.ClearContent(); Response.ContentType = "image/Gif"; Response.BinaryWrite(ms.ToArray()); } catch { g.Dispose(); image.Dispose(); } } } }
2、新建登录Logon.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Logon.aspx.cs" Inherits="CheckCode.Logon" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> <script type="text/javascript"> function reload() { var code = document.getElementById('imgCode'); code.src += '?'; } </script> </head> <body> <form id="form1" runat="server"> <div> <div style=" height:200px;"></div> <div style="float:left; width:30%; height:100px;"></div> <div style="float:left; width:40%; height:100px;"> <div><img src="CheckCodeImageExt.aspx" alt="checkCode" id="imgCode" onclick="reload();" title="点击刷新" /></div> </div> </div> </form> </body> </html>
img.src = img.src+'?';这一句使服务器重新生成图片, 问号的作用是忽悠浏览器, 不要让浏览器缓存
OK....
本文转自武沛齐博客园博客，原文链接：http://www.cnblogs.com/wupeiqi/archive/2013/04/20/3033176.html，如需转载请自行联系原作者
