Question

I am trying to use the FileSystemWatcher – and am having some luck..

The goal is to MOVE the file that gets created, from the monitored folder, to a new folder.

But… have hit 2 snags. Firstly, if I move 3 files into a folder at once (Select 3 files, ctrl+x, and then ctrl+c into my Monitor Folder), the monitor only triggers for the first file. The other 2 don’t get processed.

            FileSystemWatcher fsw = new FileSystemWatcher(FolderToMonitor);
        fsw.Created += new FileSystemEventHandler(fsw_Created);

        bool monitor = true;

        while (monitor)
        {
            fsw.WaitForChanged(WatcherChangeTypes.All, 2000);
            if (Console.KeyAvailable)
            {
                monitor = false;
            }
        }

        Show("User has quit the process...", ConsoleColor.Yellow);
        Console.ReadKey();

Is there a way to make it see all 3?

Secondly, if I move a file into the monitor folder, from a different drive, it takes a few seconds to copy the file into the folder. However, the monitor triggers as soon as the file starts copying in.. so therefore, is read only, and not ready to be moved.

Is there a way I can wait for the file to complete it’s copy into the monitor folder, before I process it?

Answer 1

According to the msdn documentation:

The Windows operating system notifies
your component of file changes in a
buffer created by the
FileSystemWatcher. If there are many
changes in a short time, the buffer
can overflow. This causes the
component to lose track of changes in
the directory, and it will only
provide blanket notification.
Increasing the size of the buffer with
the InternalBufferSize property is
expensive, as it comes from non-paged
memory that cannot be swapped out to
disk, so keep the buffer as small yet
large enough to not miss any file
change events. To avoid a buffer
overflow, use the NotifyFilter and
IncludeSubdirectories properties so
you can filter out unwanted change
notifications.

Perhaps that explains your issue?
Also note that cutting and pasting files from one directory to another is basically a mere renaming operation, therefore you should use the Renamed event to detect them.

As for your other problem: try using the Changed event together with Created, as I believe both will be raised exactly once for a file (note that moving a file from another drive in not a simple renaming operation: it’s copy and delete), so the Changed event should indicate when the file copy operation has been completed (i.e. it won’t fire until the file is complete).