public void SelectedCargoResult(object payload) { var item = payload as BaseItemInfo; if (item != null) { if (!this.Model.BillItems.Any(x => x.Cargo.Id == item.Id)) { var billitem = BillItem.New(); billitem.Cargo = item; billitem.WeightUsed = CargoConstants.WeightRates.MetricTons.Id; billitem.IsTaxable = true; this.Model.BillItems.Add(billitem); } else { NavigationManager.ShowMessage("Error", "Selected cargo already exists on the list, please retry.", MessageBoxButton.OK); } } EventAggregator.GetEvent <CommonEvents.DialogResultEvent>().Unsubscribe(SelectedCargoResult); }