protected override void OnNavigatedTo(NavigationEventArgs e) { Frame rootframe = Window.Current.Content as Frame; if (rootframe.CanGoBack) { SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Visible; } else { SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Collapsed; } viewmodel = ((Todos.ViewModels.TodoItemViewModel)e.Parameter); if (viewmodel.SelectedItem == null) { textbox_detail.Text = ""; textbox_title.Text = ""; datepicker.Date = DateTime.Now.Date; button_create.Content = "Create"; } else { textbox_detail.Text = viewmodel.SelectedItem.description; textbox_title.Text = viewmodel.SelectedItem.title; datepicker.Date = viewmodel.SelectedItem.datetime; button_create.Content = "Update"; } }