private void btnModifyBooking_Click(object sender, RoutedEventArgs e)
        {
            NewBooking win = new NewBooking(b, this);

            win.Show();
            this.Hide();
        }
        private void btnAddBooking_Click(object sender, RoutedEventArgs e)
        {
            NewBooking winB = new NewBooking(c);

            winB.Show();
            this.Close();
        }
        private void btnNewCustomer_Click(object sender, RoutedEventArgs e)
        {
            NewBooking win = new NewBooking();

            win.Show();
            this.Close();
        }