How to intercept the access to a file in a .NET Program

Question

I need to intercept when the system tries to access to a file, and do something before it happens.

Answer 1

You can use FileSystemWatcher - but this doesn't let you intercept the event and do things before hand - it only informs you after the fact that a particular file or directory has been affected in some way.

Intercepting file access is not something you can do easily.

You can write a file system filter driver, which is an unmanaged DLL which the O/S will load that can intercept operations on files or folders. However, this isn't a trivial task.

What are you trying to achieve, perhaps there's a simpler alternative?