RadTreeView & RadDragAndDropManager

[rubenhak]

Hi,

I'm using a RadTreeView with IsDragDropEnabled ="True" and need to limit dragging and dropping for certain items. Tried to attach to 

            RadDragAndDropManager.AddDragQueryHandler(...);
            RadDragAndDropManager.AddDragInfoHandler(...);
            RadDragAndDropManager.AddDropQueryHandler(..);
            RadDragAndDropManager.AddDropInfoHandler(...);

and manipulate with e.QueryResult but it does not take any effect. All the items are allowed to be dragged and dropped anywhere inside the treeview. 

I followed the sample and it does work for the GridView but doesn't on a TreeView.

Thanks,

Ruben.

[Valentin.Stoychev]

Hello rubenhak,

Please check this help article:
http://www.telerik.com/help/silverlight/radtreeview-features-drag-and-drop.html

This article can also be of help:
http://www.telerik.com/help/silverlight/raddraganddrop-events.html

Please let us know if you need more help.

Best wishes,
Valentin.Stoychev
the Telerik team

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[rubenhak]

Hi Valentin,

Thanks for the articles. It gives a better idea how does dragging and dropping implemented. However, still not clear how to control disallowing dropping on certain items on the treeview. It works fine when dragging from RadGridView to RadTreeView. When dragging/dropping inside a TreeView, the DropQuery event is not being fired at all.

Thanks,

Ruben.

[Kiril Stanoev]

Hi Ruben,

The message from the DropQuery event is handled by RadTreeView. Therefore, to receive the DropQuery event, you will have to subscribe for handled events too:

public MainPage()
{
    InitializeComponent();
    treeView1.AddHandler(RadDragAndDropManager.DropQueryEvent, new EventHandler<DragDropQueryEventArgs>(DragDropQueryEventHandler), true);
}

private void DragDropQueryEventHandler(object sender, DragDropQueryEventArgs e)
{
    // add your custom logic here
}

The last parameter in treeView1.AddHandler allows you to listen for handled events. An important note is to add using Telerik.Windows; in your usings section.

Give it a try and let me know how it works for you.

All the best,
Kiril Stanoev
the Telerik team

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[rubenhak]

Hi Kiril.

Yes, it works. 

Thanks,

Ruben