I want to know if any node validation is available here. Like if am dropping a node of category Digit over some node A which is of category Alphabets. So when am dropping that node, the target node should validate the source node if it is allowed or not, or something like this. I hope you got what am trying to say. :)
You didn’t say whether this was for Silverlight; I’ll assume it is.
I think this post will be useful: Validating external drop in Silverlight
If you are targeting WPF, however, you have a lot more flexibility, just because WPF supports drag-and-drop between controls. It’s easy – replace the standard Diagram.DraggingTool with a custom one that overrides MayCopyExternal and (if needed) MayMoveExternal.
Or for more general control over the behaviors, including side-effects to stationary objects, override DragOver and DropOnto. (That’s what you can do in Silverlight too.) There’s an example of this in the Flowgrammer sample, although it’s probably more complicated than what you want because it is concerned with maintaining a particular visual grammar.
Sorry…ya it is for silverlight 4. It looks your solutions has done it. It will work fine!! Thank you again Mr.Walter!!!