private void BtnEdit_Click(object sender, RoutedEventArgs e)
        {
            Seat seat = DGSeat.SelectedItem as Seat;

            if (SelectedSeat(seat))
            {
                Seat           oldSeat = seat.Clone() as Seat;
                EditSeatWindow esw     = new EditSeatWindow(seat, EditSeatWindow.Option.EDIT);

                if (esw.ShowDialog() != true)
                {
                    int index = IndexOfSelectedSeat(oldSeat.SeatLabel);
                    Data.Instance.SeatAvailable[index] = oldSeat;
                }
            }
            view.Refresh();
        }
        private void BtnAdd_Click(object sender, RoutedEventArgs e)
        {
            EditSeatWindow esw = new EditSeatWindow(new Seat(), EditSeatWindow.Option.ADD);

            esw.ShowDialog();
        }