Last Updated: 07 Jun 2017 08:00 by ADMIN
Created on: 16 May 2017 14:03
Category: UI for WPF
Type: Bug Report
drag and drop stopped working
We use 'xmlns:telerik=""' in our application.
The problem is that DrapAndDrop does not work anymore, no Events are fired.

Since our last release we didn't change anything at our UI and as I tried a few days ago to drag something in the application and nothing happened.

Did something change with the previous mentioned reference?
What are possible solutions?

Thank you in advance 
Posted on: 07 Jun 2017 08:00
Hi Matthias,

We don't have an example showing how to migrate to the new DragDropManger. However, you can check the DragDropManager Migration article ( It doesn't contain exact information about the old treeview events but you can use it to get basic overview of what the events do. 

You can also share some runnable code that shows what is your implementation and what events you are using. This way we can guide you what to do to migrate the drag/drop functionality. You can give this information in your support ticket.

Martin Ivanov
Posted on: 24 May 2017 12:21
Thank you for that link,

Could you please give me an explicit example code for  the transformation of a code without DragDropManager to  with DargDropManger.

In my opinion the link gives me good overview but it is quite hard to use it an already existing code.

Best Regards,
Matthias Haas
Posted on: 23 May 2017 09:50

Thank you for sharing the additional information.

This happens because since Q2 2013 the treeview no longer uses its old drag and drop API. Instead it uses the new DragDropManager. You can read more about this in the Drag and Drop help article (

Martin Ivanov
Posted on: 22 May 2017 12:17
Hello Martin,

Our account is

-	We use radTreeView Control.

-	Implementation:  <EventSetter Event="Drop" Handler="TreeItemDrop_OnHandler" />
                         <EventSetter Event="DragOver" Handler="TreeItemDragOver_OnHandler" />

-	DragAndDorpManager: I’m not sure if we use it. How can I check that?

-	Just updated to newest version but it didn’t solve the problem.

Posted on: 16 May 2017 15:35
Hello Matthias,

We don't know how you are using the drag and drop and which drag and drop exactly. Can you elaborate more on your scenario by answering the following questions? 

- What controls from the UI for WPF suite you are using?
- How the drag drop was implemented and what events you are using?
- Are you using our DragAndDropManager?
- What version you are using now and what was the previous version of UI for WPF?

If possible for you, I would ask you to open a new support ticket from your account or a new thread in the UI for WPF forums. And give the requested information there. Also, can you attach a sample project along with steps to reproduce the issue?

Thank you for any help you can provide.

Martin Ivanov,
Technical Support Engineer