检测移动文件事件

Question

I am trying to develop an application for monitoring operations on a particular folder which includes creating, deleting, modifying, moveing, duplicating and renaming.

After referring to the FileSystemWatcher API, I found that it does not provide a Move event, instead it will generate a separate Delete and Create events for the same file. Of course I can wait for a Create event each time a Delete event is detected and decide whether it is a Move event or not, but it is a little bit strange to me and the appropriate time to wait for is also a problem.

Actually I find that Dropbox is able to detect the Move event correctly even when dropbox process is not running. Nice work for Dropbox team and I wonder how do they make it work on earth.

So my purpose is quite clear : Filtering Move event from other events and making it work offline (which means when the procedure is stopped)

Answer 1

Well, a move operation is basically a "copy & delete" from the FileSystemWatcher 's point of view. Without knowing details about the implementation I bet DropBox stores a hash for each file. If a file is removed in one place and created with the same hash in another place, chances are it was moved. You could actually do the same thing.