Getting Dragged RadtreeViewItems in DropQueryEvent

[Akiono Wan]

Hello,

I would like to evaluate wether a Drop Operation on a specfic RadtreeViewItem is allowed.
I got a WPF Radtreeview with hierachical Data Binding, Multiselection and Drag&Drop occurs only within the Treeview.
Therefore I added a Event Handler to the DropQuery Event of the RadTreeview.

RadTreeView1.AddHandler(RadDragAndDropManager.DropQueryEvent, new EventHandler<DragDropQueryEventArgs>(RadTreeView_DropQuery), true);

For my Decision it is necessary to know which RadtreeviewItems are dragged. I don´t need the dragged data objects, because my decision is based on parent of each dragged RadtreeviewItem.

 

private void RadTreeView_DropQuery(object sender, DragDropQueryEventArgs e)
        {

            bool dropPossible = checkIfDropPossible(draggedRadTreeViewItems);

            if (dropPossible)
            {
                e.QueryResult = true;
            }
            else
            {
                e.QueryResult = false;
            }
}

Therefore I need a way to get the dragged RadtreeviewItems in the DropQueryEvent. I searched all e.Options members but I get the responding data objects (e.Options.Payload) only.

How can I get corresponding dragged RadTreeViewItems to the DataObjects in the DropQueryEvent? Any help is welcome.

Best Regards
Akiono Wan

[Valentin.Stoychev]

Hi Akiono Wan,

In your case the e.Options.Payload contains the List of the items that are being dragged.

Greetings,
Valentin.Stoychev
the Telerik team

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[Akiono Wan]

Hi Valentin Stoychev,

thanks for your reply, but it doesn´t fit exactly to my problem.

With e.Options.Payload I will get my own datastructure. But I need the dragged RadTreeviewItem Objects and not my own datastructure.
Therefore I need a IEnumerable<RadtreeViewItem> draggedRadtreeviewItems.

I solved the problem by extending my own datastructure with a parent member property, but I think nevertheless it could be a suitable requirement to get the corresponding dragged RadtreeviewItems and not the own datastructure only.

Regards
Akiono Wan

[Valentin.Stoychev]

Hello Akiono Wan,

Yes - this is by desing. To get the containr from the data item use the ItemContainerGenerator class. Check this help article:
http://www.telerik.com/help/silverlight/radtreeview-how-to-iterate-through-treeviewitems.html

Greetings,
Valentin.Stoychev
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.