private void partName_listbox_SelectionChanged(object sender, SelectionChangedEventArgs e) { if (partName_listbox.SelectedIndex == -1) { MessageBox.Show("Select a Part Name!"); } else { //pull batch names from the DB, then render the view for filtering SelectedPartName = partName_listbox.SelectedItem.ToString(); GCIDB.Initialize(); GCIDB.OpenConnection(); batchNames = GCIDB.GetBatchNameList(SelectedPartName); batchName_listbox.ItemsSource = batchNames; System.ComponentModel.ICollectionView batchName_view = CollectionViewSource.GetDefaultView(batchName_listbox.ItemsSource); batchName_view.Filter = batchName_CustomFilter; } }