I would think this is ok, and you can decide how often you poll, just don't do it all the time. You may use a flag for poll-only mode which reduces the polling period and disables the FileSystemWatcher, which would make it kind of universal. You could even call the same callback.

Will do, thanks!

You could create a thread, spins in a loop and reinitializes the FileSystemWatcher from time to time using Thread.Sleep in between. As FileSystemWatcher uses events this would effectively create a mix of polling and signaling.

Does anyone know how to best lock access to the object during enumeration? Eg, is it a bad/good idea to use a Monitor.Enter in the constructor and a Monitor.Exit in the dispose function? I know, I could put a lock around, but I really need this to happen automatically. Cheers.