private void ButtonPrintTicket_Click(object sender, RoutedEventArgs e)
        {
            _sm.PrintTicket(_ticketReady);

            TextBoxTimeUntil.Text = $"{_sm.CurrentTicket.ValidThru.ToShortTimeString()}";

            if (_sm.CurrentTicket.PricePaid >= 50)
            {
                MessageBox.Show($"Sie dürfen bis {_sm.CurrentTicket.ValidThru.ToString()} parken");
            }
            else
            {
                TextBoxTimeUntil.Text = "";
                MessageBox.Show("Nicht genügend Münzen eingeworfen");
            }
            _sm.Cancel();

            TextBoxTimeUntil.Text = "";
        }
 private void ButtonCancel_Click(object sender, RoutedEventArgs e)
 {
     _slotMachine.Cancel();
     FastClock.Instance.IsRunning = true;
     TextBoxTimeUntil.Text        = "Abbruch!";
 }