RadDragAndDropManager to DragDropManager question

[Chris]

I am trying to convert a bit of code from the old RadDragAndDropManager to the new DragDropManager but the documentation is really lacking and I'm having a lot of trouble figuring out what to do.

I just have a simple function that determines whether or not the user can drop a node in a RadTreeView.  I feel like this should be simple to replicate with DragDropManager, but I'm just missing something:

Tree.AddHandler(RadDragAndDropManager.DragQueryEvent, new EventHandler<DragDropQueryEventArgs>(Tree_DragQuery), true);

private void Tree_DragQuery(object sender, DragDropQueryEventArgs e)
{
    var targetTvi = e.Options.Destination as RadTreeViewItem;
    var sourceTvi = e.Options.Source as RadTreeViewItem;

    if (targetTvi == null || sourceTvi == null)
    {
        return;
    }

    if (sourceTvi.DataContext is LayerTviVM && targetTvi.DataContext is LayerTviVM)
    {
        e.QueryResult = true;
    }
    else if (sourceTvi.DataContext is ImageTviVM && targetTvi.DataContext is ImageTviVM)
    {
        // We only support drag & drop of images within the same layer
        e.QueryResult = (sourceTvi.ParentItem == targetTvi.ParentItem);
    }
    else
    {
        e.QueryResult = false;
    }
}

[Yoan]

Hi Chris,

Generally, this can be achieved by modifying the DragDropEffects of the current drag operation by using the DragOver event. 

You can achieve the functionality in your question by setting the effects of the current drag operation to None.

The usage of the drag effects can be seen here. 

Regards,
Yoan
Telerik