验证码的生成

添加这样一个页面validatecode.aspx

页面代码如下

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="validatecode.aspx.cs" Inherits="validatecode" %>

 

下面是.cs代码

using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Drawing; namespace Test { public partial class validatecode : System.Web.UI.Page { public static string code; protected void Page_Load(object sender, EventArgs e) { GetCheckCodeImage(GetCheckCode()); } public static string GetCheckCode() { 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(); } return checkCode; } #region GetCheckCodeImage public void GetCheckCodeImage(string checkCode) { if (checkCode == null || checkCode.Trim() == String.Empty) return; code = checkCode; this.Session["mccode"] = checkCode; System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 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 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("Times New Roman", 14, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Regular)); System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Red, Color.Black, 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.Black), 0, 0, image.Width - 1, image.Height - 1); System.IO.MemoryStream ms = new System.IO.MemoryStream(); image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); Response.ClearContent(); Response.ContentType = "image/Jpeg"; Response.BinaryWrite(ms.ToArray()); } finally { g.Dispose(); image.Dispose(); } } #endregion } }

下面是使用

使用页面添加如下js代码

 function changeSource(){
      document.getElementById("mmcode").src="validatecode.aspx"+'?'+Math.random();}

 

下面是页面具体使用

  <p style ="text-align :center ">Verification Code：<asp:TextBox ID ="tboxcode"
        runat ="server" Width="128px" ></asp:TextBox> <img src="ValidateCode.aspx" alt="验证码" name="yanzheng" width="73" height="23" id="mmcode" />
            <a href="javascript:changeSource();">Clcik here to change </a></p>