public async void GetAllWarden() { try { var client = new HttpClient(); client.BaseAddress = new Uri(ApplicationURL.BaseURL); HttpResponseMessage response = await client.GetAsync(ApplicationURL.GetAllWarden); string result = await response.Content.ReadAsStringAsync(); if ((int)response.StatusCode == 200) { ObservableCollection <WardenInfoModel> data_ = JsonConvert.DeserializeObject <ObservableCollection <WardenInfoModel> >(result); if (data_.Count > 0) { await ContactWardenCallback.GetAllWarden(data_); } else { await ContactWardenCallback.ServiceFaild(); } } else { await ContactWardenCallback.ServiceFaild(); await App.Current.MainPage.DisplayAlert(" ", "Data Error", "OK"); } } catch (Exception ex) { await ContactWardenCallback.ServiceFaild(); await App.Current.MainPage.DisplayAlert(" ", "Server Error", "OK"); } }