Using IFileProvider to watch a directory to get file changes

Question

I've been given an IFileProvider and I'm trying to use it monitor a directory for file updates via the Watch() method.

private void WatchDirectory(IFileProvider fileProvider, string directoryPath = @"*/MyDir/*")
{
    var token = fileProvider.Watch(directoryPath);

    token.RegisterChangeCallback(i => Console.WriteLine($"File updated: { [What goes here?] }"), null);
}

Ideally I'd receive the IFileInfo and a flag saying whether it was created, renamed, modified, or deleted; but even just the filename would be good.

The problem is I can't find any examples or documentation for accomplishing anything more than a count (which doesn't seem useful to me). Does anyone have any suggestions on how to do this?

Zygosis

Answer 1

Unfortunately, this is not supported by the IFileProvider.Watch() method and the IChangeToken interface.

You should use instead the FileSystemWatcher to detect changes by subscribing to the Changed, Created, Deleted and Renamed events.

private void WatchDirectory(string directoryPath, string filter)
{
    var fileWatcher = new FileSystemWatcher(directoryPath, filter);
    fileWatcher.Changed += this.OnFileChanged;
    fileWatcher.Created += this.OnFileChanged;
    fileWatcher.Deleted += this.OnFileChanged;
    fileWatcher.Renamed += this.OnFileChanged;

    fileWatcher.EnableRaisingEvents = true;
}

private void OnFileChanged(object sender, FileSystemEventArgs e)
{
    Console.WriteLine($"File updated: {e.Name} (ChangeType: {e.ChangeType})");
}

The FileSystemEventArgs argument received in the events contains the name of the file changed and also the type of the change (updated, created, deleted or renamed).

Copolymer