Как разместить данные с помощью httpwebrequest в c#.net

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try
           {

               string url = "http://xyz.co.in:8080/register";

               string postdata = "uid" + uid + "userid" + userid + "password" + password + "emailid" + emailid + "isotemplate"+ isotemplate + "mobileno" + mobileno +
                                  "deviceserialid" + deviceserialid + "compmacaddress" + compmacaddress + "kioskid" + kioskid + "kioskhandler" + kioskhandler + "devicename"
                                  + devicename + "devicemodel" + devicemodel;
               byte[] data = Encoding.UTF8.GetBytes(postdata);

               HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

               request.KeepAlive = false;
               request.ProtocolVersion = HttpVersion.Version10;
               request.Method = "POST";
               // turn our request string into a byte stream
               byte[] postBytes = Encoding.UTF8.GetBytes(postdata);

               // this is important - make sure you specify type this way
               request.ContentType = "application/json; charset=UTF-8";
               request.Accept = "application/json";
               request.ContentLength = postBytes.Length;
               //request.CookieContainer = Cookies;
               //request.UserAgent = currentUserAgent;
               Stream requestStream = request.GetRequestStream();

               // now send it
               requestStream.Write(postBytes, 0, postBytes.Length);
               requestStream.Close();

               // grab te response and print it out to the console along with the status code
               HttpWebResponse response = (HttpWebResponse)request.GetResponse();
               string result;
               using (StreamReader rdr = new StreamReader(response.GetResponseStream()))
               {
                   result = rdr.ReadToEnd();
               }

Что я уже пробовал:

сообщение об ошибке удаленного сервера bad 400

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