My .Net application monitors files in specified directory. If any file is about to be modified I need to backup that file.
My goal is to avoid backing up all files in the directory. I want only to backup files that will be modified, it is only a tiny percentage of all files in a folder.
As far as I see the .Net FileSystemWatcher can only detect that file is already modified, so it is too late for me to backup the file at that moment.
How do I detect the moment when the file is about to be modified, so I can backup it?
If theres no easy way of intetcepting the write operating (and I'm pretty sure there isn't, not without writing drivers like some people have commented) you could cheat and use a combination of shaddow coppies and file system watcher. Start with a shadow copy, when the file system watcher detects change, restore the shadow copy, and then do whatever you were intending after.
I know its not a solution just a work around, but youd end up with the same result, a file with the original version after a save.