c# - Async/Await with RestSharp in Windows Phone 8 -

i did search on internet, there solutions windows phone 7 don't work windows phone 8 please me out i'm doing wrong. i'm writing wp8 app consumes api mashape. i'm using restsharp nuget package. here extension methods restsharp packages await.

public static class restclientextensions {     public static task<irestresponse> executetaskasync(this restclient @this, restrequest request)     {         if (@this == null)             throw new nullreferenceexception();          var tcs = new taskcompletionsource<irestresponse>();          @this.executeasync(request, (response) =>         {             if (response.errorexception != null)                 tcs.trysetexception(response.errorexception);             else                 tcs.trysetresult(response);         });          return tcs.task;     }      public static task<t> executetaskasync<t>(this restclient @this, restrequest request) t : new()     {         if (@this == null)             throw new nullreferenceexception();          var tcs = new taskcompletionsource<t>();          @this.executeasync<t>(request, (response) =>         {             if (response.errorexception != null)                 tcs.trysetexception(response.errorexception);             else                 tcs.trysetresult(response.data);         });          return tcs.task;     } } 

here function in being called. function lies in api.cs class file.

public async task<sendmessage> sendmessage(string phone, string msg, textbox textbox) {     // create post request required headers & parameters     var request = new restrequest("sendsms/{api}.json", method.post);     request.addurlsegment("api", apikey);     request.addheader("x-mashape-key", "abcdefghixyz");     request.addparameter("msg", msg);     request.addparameter("phone", phone);      var temp = await client.executetaskasync<sendmessage>(request);     return temp; } 

here page1.xaml.cs file of needed.

private void appbarbutton_send_click(object sender, eventargs e) {     api api = new api();     sendmessage = api.sendmessage(contactnumber, textbox_message.text, textbox_message).result;     messagebox.show(a.message); } 

if directly call restsharp .executeasync() method in sendmessage() method works fine. if way, executes till await condition, returns tcs.task , complete app halts. stays way , nothing changes. idea doing wrong?

i try , await return sendmessage

 private async void appbarbutton_send_click(object sender, eventargs e)   {       api api = new api();       sendmessage = await api.sendmessage(contactnumber, textbox_message.text, textbox_message);       messagebox.show(a.message);   }