private bool AddAirplane(AirplaneModel airplaneModel)
        {
            var editWindow = new EditAirplaneWindow();
            var ctx        = (EditAirplaneViewModel)editWindow.DataContext;

            ctx.Airplane = airplaneModel;
            if (editWindow.ShowDialog() != true)
            {
                return(false);
            }

            var errs = GetModelErrors(ctx.Airplane);

            if (errs != string.Empty)
            {
                ShowError(errs, "Error! Saving cancelled. ");
                return(false);
            }

            _airplaneService.AddAirplane(airplaneModel);
            return(true);
        }
        private bool EditAirplane(AirplaneModel airplane)
        {
            var editWindow   = new EditAirplaneWindow();
            var ctx          = (EditAirplaneViewModel)editWindow.DataContext;
            var airplaneCopy = new AirplaneModel();

            CopyFields(airplane, airplaneCopy);
            ctx.Airplane = airplaneCopy;
            if (editWindow.ShowDialog() != true)
            {
                return(false);
            }
            var errs = GetModelErrors(airplaneCopy);

            if (errs != string.Empty)
            {
                ShowError(errs, "Error! Saving cancelled. ");
                return(false);
            }

            CopyFields(airplaneCopy, airplane);
            _airplaneService.EditAirplane(airplane);
            return(true);
        }