public partial class MainWindow : Window {

		public static readonly System.Windows.Media.Brush SELECTED = new SolidColorBrush(Colors.Red);
		public static readonly System.Windows.Media.Brush NOTSELECTED = new SolidColorBrush(Colors.Beige);

		public MainWindow() {
			InitializeComponent();
		}
		void rules(Button button) {
			if (button.Background == SELECTED){
				button.Background = NOTSELECTED;
				//todo
			} else {
				button.Background = SELECTED;
				//todo
			}
		}
		private void button_click(object sender, RoutedEventArgs e) {
			switch ((sender as Button).Name) {
			case "button_exit":
				Close();
				break;
			case "button_doit":
				//todo
				break;
			default:
				rules (sender as Button);
				break;
			}
		}
	}