async Task Nav() { if (i < 0) { i = 0; } ComicImage.Source = await StorageInterface.GetImageSourceFromStorageFile(arr[i++]); if (i == arr.Length) { i = 0; halted = true; PauseButton.Content = "ENDE. Neu starten?"; PauseButton.Background = new SolidColorBrush(Colors.Red); } }