用户注册验证码问题？

写了个用户注册，想添加个验证码，我用自定义验证控制判断的，提交时一直出错误，最后试了下这样根本不可以用，想问下验证码的正确使用方法是什么样的呢，最好用个实例，谢了·

解决方案 »

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<%@ Page Language="C#" AutoEventWireup="true" CodeFile="showcode.aspx.cs" Inherits="showcode" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
showcode.aspx
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Image ID="Image1" runat="server" ImageUrl="CreateCheckCode.aspx" />

        <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="刷新验证码" />
        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
        <asp:Button ID="Button2" runat="server" onclick="Button2_Click" Text="Button" />
    </div>
    </form>
</body>
</html>showcode.aspx.csusing 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;public partial class showcode : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Redirect("showcode.aspx");
    }
    protected void Button2_Click(object sender, EventArgs e)
    {        if(this.TextBox1.Text.Equals(Session["uid"].ToString()))
        {
            Response.Write("验证成功!");
        }
        else
        {
            Response.Write("验证失败!");
        }
    }
}
CreateCheckCode.aspx<%@ Page Language="C#" AutoEventWireup="true" CodeFile="CreateCheckCode.aspx.cs" Inherits="_Default" %><!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>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

    </div>
    </form>
</body>
</html>CreateCheckCode.aspx.csusing 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;
using System.Drawing.Design;
using System.Drawing.Drawing2D;
using System.Drawing.Printing;
using System.Drawing.Imaging;
using System.IO;
public partial class _Default : System.Web.UI.Page
{
    private string CreateCheckCodeString()
    { //定义用于验证码的字符数组
        char[] AllCheckCodeArray ={ '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'};
        //定义验证码字符串
        string randomcode = "";
        Random rd = new Random();
        //生成4位验证码字符串
        for (int i = 0; i < 4; i++)
            randomcode += AllCheckCodeArray[rd.Next(AllCheckCodeArray.Length)];
        return randomcode;
    }
    //生成验证码图片
    protected void Page_Load(object sender, EventArgs e)
    {
        //定义图片的宽度
        int ImageWidth = 55;
        //定义图片高度
        int ImageHeigh = 22;
        //定义字体，用于绘制文字
        Font font = new Font("Arial", 12, FontStyle.Bold);
        //定义画笔，用于绘制文字
        Brush brush = new SolidBrush(Color.Black);        //定义钢笔，用于绘制干扰线        Bitmap BitImage = new Bitmap(ImageWidth, ImageHeigh);
        //从图像获取一个绘画面
        Graphics graphics = Graphics.FromImage(BitImage);
        //清除整个绘图画面并用颜色填充
        graphics.Clear(ColorTranslator.FromHtml("#F0F0F0"));//这里从HTML代码获取color对象
        //定义文字的绘制矩形区域
        RectangleF rect = new RectangleF(5, 2, ImageWidth, ImageHeigh);
        string key = CreateCheckCodeString();
        Session["uid"] = key;
        graphics.DrawEllipse(new Pen(Color.Blue),0,0,50,20);
        graphics.DrawString(key, font, brush, rect);
        //保存图片为gif格式
        BitImage.Save(Response.OutputStream, ImageFormat.Gif);
        //释放对象
        graphics.Dispose();
        BitImage.Dispose();
    }
}