Common工具类的验证码类的使用（未实现验证）

验证码接收

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using CZBK.ItcastProject.Common;

namespace CZBK.ItcastProject.WebApp._2015_5_29
{
    /// <summary>
    /// ValidateImageCode 的摘要说明
    /// </summary>
    public class ValidateImageCode : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            ValidateCode validatecode = new ValidateCode();
            string code= validatecode.CreateValidateCode(4);
            validatecode.CreateValidateGraphic(code, context);
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

登录页面（实现验证码点击替换）

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title></title>
    <script type="text/javascript">
        window.onload = function () {
            var validateCode = document.getElementById("validateCode");
            validateCode.onclick = function () {
                document.getElementById("imgCode").src = "ValidateImageCode.ashx?d=" + new Date().getMilliseconds();
            }
        }
    </script>
</head>
<body>
    <form method="post" action="UserLogin.ashx">
        用户名:<input type="text" name="txtName" /><br />
        密码:<input type="password" name="txtPwd" /><br />
        验证码:<input type="text" name="txtCode" /><img src="ValidateImageCode.ashx" id="imgCode" />
        <a href="javascript:void(0)" id="validateCode">看不清</a><br />
        <input type="submit" value="登录" />
    </form>
</body>
</html>