ASP.NET网页验证码常用方法

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

using System.Drawing.Drawing2D;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using Px_CSLibrary.Public;
public partial class CheckCode : System.Web.UI.Page
{

protected void Page_Load(object sender, EventArgs e)
{
ValidatedCode v = new ValidatedCode();
string checkNum = v.CreateVerifyCode();            //取随机码
Session["Checkcode"] = checkNum;
HttpCookie cookCode = new HttpCookie("Check");
cookCode.Values.Add("code", checkNum);//把随机验证码保存Cookie
cookCode.Expires = DateTime.Now.AddMilliseconds(60000);
Response.Cookies.Add(cookCode);

v.CreateImageOnPage(checkNum, this.Context);       // 输出图片

}

}

<dd> <img id="CheckCode" alt="验证码" width="85px" height="25px" style="cursor: pointer" src="CheckCode.aspx" onclick="GetCode()" /></dd>
<dd>
<a href="javascript:void(0)" onclick="GetCode();">刷新</a>
</dd>