If you save using SaveToXml method you could parse the XML files yourself if you want to avoid loading them into the diagram for some reason (implementing a search function?).

If you are trying to avoid loading into currently visible diagram instance, note that you can create and load an off-screen Diagram without showing it inside a DiagramView. Then look for node data in the off-screen Diagram using its .NET API, while only your main diagram shows on screen.

Regards,
Slavcho
Mindfusion