c# – 在致电Google GCM时未经授权

我尝试使用Google GCM发送推送通知.但得到一个WebException,说远程服务器返回401 unautorized.我无法理解为什么它不起作用.

有谁知道它为什么不起作用？

这是我的代码：

ServicePointManager.ServerCertificateValidationCallback += new RemoteCertificateValidationCallback(ValidateServerCertificate);

           HttpWebRequest Request = (HttpWebRequest)WebRequest.Create("https://android.googleapis.com/gcm/send");


            Request.Method = "POST";
            Request.KeepAlive = false;

            string postData = "{ 'registration_ids': [ '"+registrationId+"' ], 'data': {'message': '"+message+"'}}";

            byte[] byteArray = Encoding.UTF8.GetBytes(postData);

            Request.ContentType = "application/json";
            //Request.ContentLength = byteArray.Length;


            //Request.Headers.Add(HttpRequestHeader.Authorization, "GoogleLogin auth=" + AuthString);
            Request.Headers.Add(HttpRequestHeader.Authorization, "Authorization: key=AIzaSyCEygavdzrNM3pWNPtvaJXpvW66CKnjH_Y");
            //-- Delegate Modeling to Validate Server Certificate --//


            //-- Create Stream to Write Byte Array --// 
            Stream dataStream = Request.GetRequestStream();
            dataStream.Write(byteArray, 0, byteArray.Length);
            dataStream.Close();

            //-- Post a Message --//
            WebResponse Response = Request.GetResponse();
            HttpStatusCode ResponseCode = ((HttpWebResponse)Response).StatusCode;
            if (ResponseCode.Equals(HttpStatusCode.Unauthorized) || ResponseCode.Equals(HttpStatusCode.Forbidden))
            {
                var text = "Unauthorized - need new token";

            }
            else if (!ResponseCode.Equals(HttpStatusCode.OK))
            {
                var text =  "Response from web service isn't OK";
            }

            StreamReader Reader = new StreamReader(Response.GetResponseStream());
            string responseLine = Reader.ReadLine();
            Reader.Close();