c# - Post Json Data using volly library to wcf rest service -

i migrating asynctask volley.in application want json data wcf rest service.my code below

stringrequest postrequest = new stringrequest(request.method.post, url,             new response.listener<string>() {                 @override                 public void onresponse(string response) {                     // response                     log.d("response", response);                 }             },             new response.errorlistener() {                 @override                 public void onerrorresponse(volleyerror error) {                     // todo auto-generated method stub                     if(error.networkresponse != null && error.networkresponse.data != null){                         volleyerror error2 = new volleyerror(new string(error.networkresponse.data));                         error = error;                     }                     log.d("error", "error => " + error.tostring());                 }             }     ) {         @override         protected map<string, string> getparams()         {             map<string, string>  params1 = new hashmap<>();             params1.put("userid", "123");             params1.put("password", "123");             return params1;         }         @override         public map<string, string> getheaders() {             hashmap<string, string> headers = new hashmap<string, string>();             headers.put("content-type", "application/json; charset=utf-8");             return headers;         }     } ; 

but getting error 'http error 400. request has invalid header name' wcf service...

sorry late reply.there problem wcf rest service give backslash encoded json volley didnt got json content type