Cancel drop event

[Roman Gomolko]

Hi.

I got interesting problem using RadTreeView and RadDragAndDropManager.
I want to implement verification of drop operation.

• user drops one item to another
• Confirmation
• Cancel drop operation if needed.

I'm using TreeView bounded to ObservableCollection<T>.
I'm attached to OnCollectionChanged event in the collection and to OnDragEnded in TreeView

As I can see in my test application OnCollectionChanged event fires before OnDragEnded. It's seems that here (RadDragAndDropManager or RadTreeView) should be another event fired before changing data.

Could you help me with it?

Best regards, Roman

[Miroslav]

Hi Roman Gomolko,

There are two ways to handle delayed drag-drop. They both involve cancelling the default DragDrop action and carrying it out if the user confirms the drag-drop. Cancelling the default drag-drop action for the TreeView is done by handling the PreviewDragEnded event.

I modified one of our online example to show this. In one of the projects a ContextMenu is shown, while the other displays a  Confirm dialog (what I gather you need).

Hopefully you will find the two projects useful.

All the best,
Miroslav
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Watch a video on how to optimize your support resource searches and check out more tips on the blogs.