DevExpress XtraTreeList 节点拖拽

private void TreeList1_DragOver(object sender, DragEventArgs e)
{
	TreeList treelist = sender as TreeList;
	TreeListNode dragNode = e.Data.GetData(typeof(TreeListNode)) as TreeListNode;

	Point p = treelist.PointToClient(MousePosition);
	TreeListNode  targetNode = treelist.CalcHitInfo(p).Node;

	if (dragNode != null && targetNode != null && dragNode!=targetNode)
	{
		object obj = targetNode.GetValue("对象");
		if(obj is IProxyCNGlbGlobeLayer ||obj is IProxyCNGlbGlobeObject)
			e.Effect=DragDropEffects.None; 
	}
}