private void buttonAddCategory_Click(object sender, RoutedEventArgs e) { var model = BookmarkerModel.GetDefault(); var view = new CreateCategoryView(); var popup = FlyoutUtils.CreateFlyout(this.BottomAppBar, (Button)sender, view); view.CreateClicked += (_, __) => { if (!view.Validate()) { return; } var category = view.CreateBookmarkCategory(); model.Categories.Add(category); var nowait = model.SaveAsync(); popup.IsOpen = false; }; popup.IsOpen = true; }