public async void RemoveSubject() { ContentDialog RemoveDialog = new ContentDialog { Title = "Reference removal", Content = "There can be many references to this Subject in courses, these references will be dropped, and can not be undone. Are you sure to continue?", CloseButtonText = "No", PrimaryButtonText = "Yes" }; ContentDialogResult result = await RemoveDialog.ShowAsync(); if (result == ContentDialogResult.Primary) { SubjectManager.RemoveSubject(selected); } }