In this post Tim Heuer expalins about confirming delete with DataForm.
When DeleteItem is called on DataForm (via the built-in toolbar or via your own methods), it deletes the current item. After all, that’s what you told it to do! The problem is that the delete is fast and there is no easy “undo” method.
Luckily, DataForm provides a method interceptor for us: DeletingItem.