System.Net.WebException: 基础连接已经关闭: 接收时发生错误。 ---> System.IO.IOException: 无法从传输连接中读取数据: 远程主机强迫关闭了一个现有的连接。。 ---> System.Net.Sockets.SocketException: 远程主机强迫关闭了一个现有的连接。
   在 System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
   在 System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   --- 内部异常堆栈跟踪的结尾 ---
   在 System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   在 System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   在 System.Net.Connection.SyncRead(HttpWebRequest request, Boolean userRetrievedStream, Boolean probeRead)
   --- 内部异常堆栈跟踪的结尾 ---
   在 System.Net.HttpWebRequest.GetResponse()
   在 System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials credentials, IWebProxy proxy, RequestCachePolicy cachePolicy)
   在 System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn)
   在 System.Xml.XmlTextReaderImpl.FinishInitUriString()
   在 System.Xml.XmlReaderSettings.CreateReader(String inputUri, XmlParserContext inputContext)
   在 ZT.DAL.ShenDa.Auth.AuthUser(String UserName, String PassWord, String& Msg)
   在 ZT.WebApi.Controllers.AuthController.AuthUser()*****


代码
HttpWebResponse response = null;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url + (string.IsNullOrEmpty(postDataStr) ? "" : "?") + postDataStr);
            request.Timeout = 30000; // 设置超时时间,单位毫秒。默认100000毫秒，100秒
            try
            {
                request.Method = "GET";
                request.ContentType = "application/xml";
                request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)";
                ServicePointManager.CheckCertificateRevocationList = true;
                ServicePointManager.DefaultConnectionLimit = 100;
                ServicePointManager.Expect100Continue = false;
                //ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
                request.KeepAlive = true;
                request.ProtocolVersion = HttpVersion.Version10;
                request.Referer = "";
                request.AllowAutoRedirect = true;
                request.Timeout = 5 * 60 * 1000; // 5 minutes

                response = (HttpWebResponse)request.GetResponse();

                Stream myResponseStream = response.GetResponseStream();
                StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
                string retString = myStreamReader.ReadToEnd();

                myStreamReader.Close();
                myStreamReader.Dispose();
                myResponseStream.Close();
                myResponseStream.Dispose();
                return retString;