C# solution for analysing files as they are written/modified

I have several projects that require me to monitor files, and then edit them as they are getting written to disk. I have a feeling that what I am looking for is operationally the same as how anti-virus tools operate. Let me give more details: 1) I need to trap all files saved by Office application, and then add specific company tags to the headers/footers of each docum开发者_JAVA技巧ent as they are getting written to disk. 2) I need to know immediately when an editable file (of pretty much any type) is written to disk, so that I can undertake some scanning operations to check if files content meets certain company policies.

In short, you can see that I need to process any user files as they are being written to disk.

Here is my problem. I want to use C# for this task, but I am not sure if it has the ability to meet my requirements. Everything I have seen on the net is geared towards lower-level C programming, which I specifically want to avoid due to time constraints for this project. Anyone aware of how to easily do this task in C#? Is it even feasible (ie too high-level a language, too slow a language etc.)?

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Performance won't be the issue. I guess I'd question the entire process- it sounds like a recipe for disaster. You can easily hack something together in C# using a FileSystemWatcher in a matter of minutes, but it will be fraught with issues. AV software is bad enough about locking files and screwing up various software, and it's not even trying to modify the file. How do you know when the other app is "done" writing the file? What do you do when you've got the file locked and something else breaks because it can't get access?

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Have you looked at the FileSystemWatcher?

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C# can easily do this. Look at the FileSystemWatcher class (http://msdn.microsoft.com/en-us/library/system.io.filesystemwatcher.aspx).