protected async Task ExecuteLoadQuestionsCommand() { if (IsBusy) { return; } IsBusy = true; try { Questions.Clear(); object responce = await QuestionsService.DoQuestionsGetRequest(LessonId); if (responce is ErrorMessage) { ErrorMessage error = responce as ErrorMessage; Debug.WriteLine(error.ErrorCode + " " + error.ErrorDescription); } else { var questions = responce as IEnumerable <Question>; foreach (var question in questions) { Questions.Add(question); } } MessagingCenter.Send <QuestionsListViewModel>(this, "QuestionsLoaded"); } catch (Exception ex) { Debug.WriteLine("[!] ExecuteLoadQuestionsCommand --- " + ex); } finally { IsBusy = false; } }