How to disable the dropping of an node next to the root node of my TreeView?

[koala]

Hello,

I'm using the RadTreeView with only ONE root node. My ItemsSource is FolderData. FolderData has only one Item - the root node. I'm using

DragDropManager.AddDragOverHandler(this.FolderRadTreeView, new Telerik.Windows.DragDrop.DragEventHandler(OnDragOver), true);

​ for allowing the dropping in special nodes. 

 

How can I disable the dropping next to root node? I want to avoid to have more than one root nodes. Is it possible?

[Peshito]

Hi,

You can prevent your items from being dropped outside the root node by implementing OnDragOver like shown bellow for instance:

private void OnDragOver(object sender, Telerik.Windows.DragDrop.DragEventArgs e)
        {
            var options = DragDropPayloadManager.GetDataFromObject(e.Data, TreeViewDragDropOptions.Key) as TreeViewDragDropOptions;
            if (options != null)
            {
                if (options.DropTargetItem.Header.ToString() == "Sport Categories" && options.DropPosition != DropPosition.Inside)
                {
                    options.DropAction = DropAction.None;
                    options.DropPosition = DropPosition.Undefined;
                    options.UpdateDragVisual();
                }
            }
        }

The important thing here is that you should change the DropAction and DropPosition depending on the DropTargetItem.

Attached is a sample project illustrating the above approach.

Hope it helps.

Regards,
Peshito
Telerik