public async override void OnNavigatedTo(object navigationParameter, Windows.UI.Xaml.Navigation.NavigationMode navigationMode, Dictionary<string, object> viewModelState) { base.OnNavigatedTo(navigationParameter, navigationMode, viewModelState); if (viewModelState != null) { if (navigationMode == NavigationMode.Refresh) { var personErrorsCollection = RetrieveEntityStateValue<IDictionary<string, ReadOnlyCollection<string>>>("personErrorsCollection", viewModelState); if (personErrorsCollection != null) { SelectedPerson.SetAllErrors(personErrorsCollection); } } } // Note: Each time app selects from main page (PersonListPage) detail page (PersonDetailPage) is recreated. // Meaning that constructor is run and SelectedPerson is null. // If SuspendAndTerminate (e.g. debug mode) SelectedPerson is saved to SessionState (because of [RestorableState] attribute). // Therefore, if SelectedPerson has been saved, use it instead of doing GetPersonAsync. if (SelectedPerson == null) { string errorMessage = string.Empty; int personId = (int)navigationParameter; if (personId == 0) { SelectedPerson = new Person(); SelectedPerson.ValidateProperties(); RunAllCanExecute(); } else { try { LoadingData = true; CrudResult = await _personRepository.GetPersonAsync(personId); SelectedPerson = JsonConvert.DeserializeObject<List<Person>>(CrudResult.Content.ToString()).FirstOrDefault<Person>(); } catch (HttpRequestException ex) { ErrorMessageTitle = ErrorMessagesHelper.HttpRequestExceptionError; //TODO: Log stack trace to database here ErrorMessage = string.Format("{0}", ex.Message); } finally { LoadingData = false; } if (ErrorMessage != null && ErrorMessage != string.Empty) { MessageDialog messageDialog = new MessageDialog(ErrorMessage, ErrorMessageTitle); await messageDialog.ShowAsync(); _navService.GoBack(); } } } RunAllCanExecute(); }
// When New button is pressed private void OnNewPerson() { SelectedPerson = new Person(); SelectedPerson.ValidateProperties(); RunAllCanExecute(); }