FileSystemWatcher - is File ready to use

Question

When a file is being copied to the file watcher folder, how can I identify whether the file is completely copied and ready to use? Because I am getting multiple events duri

Answer 1

Note: this problem is not solvable in generic case. Without prior knowledge about file usage you can't know if other program(s) finished operation with the file.

In your particular case you should be able to figure out what operations File.Copy consist of.

Most likely destination file is locked during whole operation. In this case you should be able to simply try to open file and handle "sharing mode violation" exception.

You can also wait for some time... - very unreliable option, but if you know size range of files you may be able to have reasonable delay to let Copy to finish.

You can also "invent" some sort of transaction system - i.e. create another file like "destination_file_name.COPYLOCK" which program that copies file would create before copying "destination_file_name" and delete afterward.