private void RemoveContractor_Click(object sender, RoutedEventArgs e) { ExternalBusiness contractor = (ExternalBusiness)ContractorsView.SelectedItem; if (contractor != null) { if (contractor.getOrderIDsCount() != 0) { MessageBox.Show("Please reassign their orders to other bakers!"); } else if (MessageBox.Show("Are you sure you want to delete this contractor from the system?", "", MessageBoxButton.YesNo) == MessageBoxResult.Yes) { DB.GetListOfContractors().Remove(contractor); UpdateContractorsView(); } } }