private void AddOperation()
        {
            switch (view.entity)
            {
            case Entity.Room:
                Room room = view.RoomAddOrUpdateEnter();
                roomDAO.Create(room);
                break;

            case Entity.Guest:
                Guest guest = view.GuestAddOrUpdateEnter();
                guestDAO.Create(guest);
                break;

            case Entity.Booking:
                Booking booking = view.BookingAddOrUpdate();
                bookingDAO.Create(booking);
                break;
            }
            view.Success();
        }