Programmatically View/Close Open Files in Network Folder

Question

I've got an application designed in VB.Net and I'm using part of it to programmatically rename folders, but the user gets an error if someone has a file open from that folder. Is there a way to view all of the files that are open within a specific network folder? If so, is there a way to programmatically close those files, or at least see who has the files open? Thanks for any help you can provide.