Question

I’m looking for a reliable way of looking for changes in a directory.

I have tried using the FileSystemWatcher, but it’s rather inaccurate when many small files are created, changed or deleted. It misses about 1 or 2 % of the files in my tests. That is quite a lot when you are adding or changing thousands of files rapidly.

I have tried polling for changes at different intervals 500 ms, 2000 ms etc. In this case I get too many hits. That might have something to do with the resolution of timestamps on the FileInfo object.

So my question is; is it possible, using the .NET Framework, to get the the changes to a directory reliably?

—
Christian

Answer 1

Have you tried increasing the InternalBufferSize?
What size have you set it to?

From MSDN:

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Note that a FileSystemWatcher may miss
an event when the buffer size is
exceeded. To avoid missing events,
follow these guidelines: Increase the
buffer size by setting the
InternalBufferSize property. Avoid
watching files with long file names,
because a long file name contributes
to filling up the buffer. Consider
renaming these files using shorter
names.

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Keep your event handling code as short as possible.