private async void ListaDeClasses() { try { Classes = await Matricula.ListaDeClasses(); Pk_Classe.ItemsSource = Classes; } catch (JsonException ex) { DependencyService.Get <IMessageError>().LongAlert(ex.Message); } catch (HttpRequestException ex) { DependencyService.Get <IMessageError>().LongAlert(ex.Message); } catch (Exception ex) { //DependencyService.Get<IMessageError>().LongAlert(ex.Message); } finally { } }