C#（ASP.NET） 下载数据

Internet 类
using System;
using System.Collections.Generic;
using System.Collections;
using System.Text;
using System.Net;
using System.IO;
using System.Text.RegularExpressions;
using System.Threading;
namespace DownData
{
    class internet
    {
        #region 过滤空格
        public static string FilterKG(string msg)
        {
            string ms = Regex.Replace(msg, @"\s", "");
            return ms;
        }
        #endregion
        #region 可变地方
        // 提取HTML代码中的网址
        public static ArrayList GetHyperLinks(string content)
        {
            ArrayList al = new ArrayList();
            int b = 0;
            int a = 0;
            int index = 0;
                while (true)
            {
                a = content.IndexOf("<a href=\"javascript:click_history('", b);
                if (a != -1)
                {