or
<DataTemplate x:Key="MultiComboBoxView"> <telerik:RadComboBox ItemsSource="{Binding ValueEnum}" Width="220" Height="30" ItemTemplate="{StaticResource RadComboBoxItemTemplate}"> <telerik:RadComboBox.SelectionBoxTemplate> <DataTemplate> <TextBlock Text="{Binding SelectedItemsText}" /> </DataTemplate> </telerik:RadComboBox.SelectionBoxTemplate> </telerik:RadComboBox></DataTemplate>private void ListBoxIssue_OnPreviewDrop(object sender, DragEventArgs e){ var droppedObject = DragDropPayloadManager.GetDataFromObject(e.Data, typeof(CommsItem)); List<CommsItem> listCommsItem = ((List<object>) droppedObject).Cast<CommsItem>().ToList(); //droppedObject is an object, which is of List<Object>, which the objects in the list are CommsItem foreach (CommsItem commsItem in listCommsItem) { if (commsItem.Serial == "2008") { e.Handled = true; e.Effects = DragDropEffects.None; } else { e.Handled = false; e.Effects = DragDropEffects.All; } }}