WebClient卡死
使用WebClient进行模拟浏览器，但总是出现直接卡死的问题，超时设置了
我扩展了基本的WebClient，下面是 关键代码

protected override WebRequest GetWebRequest(Uri address)

        {

            InitHeader();

            Request = (HttpWebRequest)base.GetWebRequest(address);

            Request.MaximumAutomaticRedirections = 1000;

            if (Timeout <= 0)

                Timeout = 60;

            Request.Timeout = Timeout * 1000;

            Request.ReadWriteTimeout = Timeout * 1000;

            Request.AllowAutoRedirect = AllowAutoRedirect;

            Request.CookieContainer = this._cookieContainer;

            Request.KeepAlive = true;

            Request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

            if (address.ToString().StartsWith("https"))

            {

                Credentials = CredentialCache.DefaultNetworkCredentials;

                ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;

                ServicePointManager.ServerCertificateValidationCallback = callback;

            }

            return Request;

        }

protected override WebResponse GetWebResponse(WebRequest request)

        {

            Response = (HttpWebResponse)base.GetWebResponse(request);

            if (Response != null)

            {

                this._cookieContainer.Add(Response.Cookies);

            }

            return Response;

        }

就这样最普通的使用

new WebClientEx().DownloadString("xxxxx")

有时候都会卡死，就是直接卡那儿不动了
把上面放线程里面，直接结束线程也不行
求教大神怎样才能避免卡死？