asp.net random Verification code (using ASHX)

Validatecode.ashx

<%@ WebHandler language= "C #" class= "Validatecode"%>
Using System;
Using System.Data;
Using System.Web;
Using System.Collections;
Using System.Web.Services;
Using System.Web.Services.Protocols;
Using System.Drawing;

public class Validatecode:ihttphandler
{

public void ProcessRequest (HttpContext context)
{
Context. Response.Cache.SetCacheability (Httpcacheability.nocache)//special attention, such as not add, click to verify the picture ' see not clear for another ', no effect.
This. Createcheckcodeimage (Generatecheckcode);
}

        public bool IsReusable
         {
            get
             {
                 return false;
           }
       }
        private String Generatecheckcode (HttpContext context)
         {
            int Number
            char Code;
            string checkcode = String.Empty;

System.Random Random = new Random ();

for (int i = 0; i < 6; i++)
{
Number = random. Next ();