在写网络爬虫，无法完成递归抓取，求大神解救！

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;
using System.IO.Compression;
using System.Net;
using System.Windows.Forms;
using System.Web;
namespace SearchEngine
{
    class Crawl
    {
        string patternCode = @"<meta[\s\S]+?charset=[\s]*[""]?(.*?)""[\s]*[\S]?>";//用于分析网站编码
        string patternUrl = "<a\\s+href\\s*=\\s*\"?(.*?)[\"|>]";
        //content="text/html; charset=gb2312"
        string filePath = @"E:\学习\各种项目\智能搜索\htmldownload\";//文件保存路径
        string dlErrorName = @"E:\学习\各种项目\智能搜索\htmldownload\downloadErrorLog.txt";
        string getCodeErrorName = @"E:\学习\各种项目\智能搜索\htmldownload\getCodeErrorLog.txt";
        /// <summary>
        /// 下载指定url的html文档，并保存在本地
        /// </summary>
        /// <param name="url"></param>
        /// <returns>返回html文本</returns>
        public string download(string url)
        {
            string encoding="ASSIC";
            string html=string.Empty;
            try
            {
                
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.Timeout = 5000;
                request.Method = "get";
                request.ContentType = "text/html";
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream resStream = response.GetResponseStream();
                StreamReader strRead;
                encoding = getEncoding(url);
                //判断网页是否经过gzip压缩，如果是则解压缩
                if (response.ContentEncoding != null && response.ContentEncoding.Equals("gzip", StringComparison.InvariantCultureIgnoreCase))
                {
                    strRead = new StreamReader(new GZipStream(resStream, CompressionMode.Decompress), Encoding.GetEncoding(encoding), true);
                }
                else
                    strRead = new StreamReader(resStream, Encoding.GetEncoding(encoding));
                html = strRead.ReadToEnd();
                resStream.Close();
                //MessageBox.Show("1");
                saveHtml(html, encoding);
                analyseLink(html);
            }
            catch (Exception ex)
            {
                /*一旦产生异常就将异常信息写入错误日志*/
                try
                {
                    FileStream fs = new FileStream(dlErrorName, FileMode.Append, FileAccess.Write);
                    StreamWriter sw = new StreamWriter(fs);
                    sw.WriteLine(ex.Message + url + "||");
                    sw.Close();
                    fs.Close();
                }
                catch (Exception e)
                {
                    return "";
                }
            }
            return html;
        }        /// <summary>
        /// 提取网页中的链接
        /// </summary>
        /// <param name="html">传入的字符串</param>
        private void analyseLink(string html)
        {
            Regex urlReg = new Regex(patternUrl, RegexOptions.IgnoreCase | RegexOptions.Multiline);
            MatchCollection matches = urlReg.Matches(html);
            foreach (Match match in matches)
            {
                string url = match.Groups[1].Value;
                download(url);
            }
        }        static int name = 1;//将保存的文件命名
        /// <summary>
        /// 讲指定的网页信息保存至本地
        /// </summary>
        /// <param name="html">需要保存的网页信息字符串</param>
        /// <param name="url">网页的地址</param>
        public void saveHtml(string html,string code)
        {
            string filename = filePath + name.ToString() + ".htm";
            StreamWriter sw = new StreamWriter(filename, false, Encoding.GetEncoding(code));
            sw.Write(html);
            sw.Close();
            name++;
        }        /// <summary>
        /// 根据url获取网页编码
        /// </summary>
        /// <param name="url">网页的域名地址</param>
        /// <returns>返回string类型的编码</returns>
        public string getEncoding(string url)
        {
            HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse wrs = (HttpWebResponse)wr.GetResponse();
            string code = "utf-8";
            try
            {
                Stream stream = wrs.GetResponseStream();
                StreamReader sr = null;
                if (wrs.ContentEncoding != null&&wrs.ContentEncoding.Equals("gzip",StringComparison.InvariantCultureIgnoreCase))
                {
                    sr=new StreamReader(new GZipStream(stream, CompressionMode.Decompress));
                }
                else
                    sr=new StreamReader(stream);
                string line;
                Regex regex = new Regex(patternCode, RegexOptions.IgnoreCase|RegexOptions.Multiline);
                Match m;
                while ((line = sr.ReadLine())!=null)
                {
                    
                    if (regex.IsMatch(line))
                    {
                        m = regex.Match(line);
                        code = m.Groups[1].Value;
                        break;
                    }
                }
            }
            catch (Exception ex)
            {
                try
                {
                    FileStream fs = new FileStream(getCodeErrorName, FileMode.Append, FileAccess.Write);
                    StreamWriter sw = new StreamWriter(fs);
                    sw.WriteLine(ex.Message + " " + url + "||");
                    sw.Close();
                    fs.Close();
                }
                catch
                {
                    return "";
                }
            }
            return code;
        }
    }
}我用的根地址是http://www.sohu.com/ 这个页面是可以抓取并且保存在本地的，然后我调试了一下 发现第二次调用函数getEncoding(string url)的时候 程序会暂停在HttpWebResponse wrs = (HttpWebResponse)wr.GetResponse();不动 但是并没有报出异常，求解啊