private async void submit_Click(object sender, RoutedEventArgs e) { string uname = username.Text; string rad = radius.Text; var js = new UnameRadius { username = uname, rad = Int32.Parse(rad), lat = 13.351320074, lon = 74.79314491152, accurate = 10 }; json = JsonConvert.SerializeObject(js); this.Frame.Navigate(typeof(waiting)); using (HttpClient hc = new HttpClient()) { hc.DefaultRequestHeaders .Accept .Add(new MediaTypeWithQualityHeaderValue("application/json")); var response = await hc.PostAsync(URI, new StringContent(json)); } }