急！！！！asp.net验证码 - .NET技术 / ASP.NET

谁能给我一个完整的asp.net 的验证码

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祝你好运~~

C# code:

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;
using System.Drawing.Imaging; //添加这2个东西.
using System.IO;
using System.Text;


public partial class yanzhengma : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
CreateCheckCodeImage(GenerateCheckCode());
}
private string GenerateCheckCode()
{
string VChar = "1,2,3,4,5,6,7,8,9,q,w,e,r,t,y,u,i,o,p,a,s,d,f,g,h,j,k,l,z,x,c,v,b,n,m";
string[] vc = VChar.Split(',');
string v = "";
Random random = new Random();

for (int i = 0; i < 4; i++)
{
v += vc[random.Next(0, vc.Length - 1)];
}
Session["VNum"] = v;

return v;
}

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)), 22);
System.Dr