It must be a common need to maintain a logical hierarchy (i.e. enforce business rules) while allowing drag drop for reorder in a treeview. I have tried implementing some by setting allowDrag/allowDrop on nodes programmatically and setting allowDragDrop/allowDragReordering for the component on the .aspx page, but have not yet found a solution that controls which nodes can be draggable to particular locations in the tree.

What is the popular method for implementing business rules on treeview drag/drop? Simply to allow/reject the move after it is done on the client or server side? Or Is it possible to configure a treeview for example, such that child nodes can be dragged to be reordered amongst other child nodes within the same parent, but NOT dropped inside another parent node, or such that parent nodes can be dragged to be reordered amongst siblings but NOT dropped inside one another?

Just a general standard mechanism would be sufficient as an answer here-- no need to post/analyze code at this point.