正则抓取网页所有href和src

string UserAgent = "Mozilla/5.0 (Windows NT 5.2; rv:29.0) Gecko/20100101 Firefox/29.0";
    string ContentType = "";

    Uri strReqUrl = new Uri("http://m.lhrb.ufstone.net/");
    protected void Application_BeginRequest(object sender, EventArgs e)
    {

        Uri u = new Uri(strReqUrl, Request.RawUrl);
        byte[] b = getVerificationCode(u);

        //MemoryStream ms = new MemoryStream(b);
        //Response.ClearContent();
        //Response.ContentType = ContentType;
        //Response.BinaryWrite(b);

        StringBuilder strHtml = new StringBuilder(Encoding.GetEncoding("gb2312").GetString(b));
        StringBuilder sb = new StringBuilder();
        GetHtmlUrl(ref strHtml);
        Response.Write(strHtml.ToString());
        Response.End();
    }
    public byte[] getVerificationCode(Uri url)
    {
        WebClient MyWebClient = new WebClient();
        MyWebClient.Headers.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
        MyWebClient.Headers.Add("Accept-Language", "    zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3");
        MyWebClient.Headers.Add("User-Agent", this.UserAgent);
        MyWebClient.Credentials = CredentialCache.DefaultCredentials;
        try
        {
            Byte[] pageData = MyWebClient.DownloadData(url.AbsoluteUri);
            ContentType = MyWebClient.ResponseHeaders["Content-Type"];
            return (pageData);
        }
        catch
        {
            return null;
        }
    }