In Vb.Net How to know if the file hasnt been changed for x seconds?

Question

I am programming something which involves certain files changing every second. Now, if the files are not changed for, say, 10 seconds it means that some error has occured somewhere, externally. So, I want the user to know about it. How can I implement this?

Sorry cant add comments due to some problem.

@Jeremy - Very small. Precisely, It wont exceed 10-15 characters.

Answer 1

Check the LastWriteTime of the file:

If Date.Now.subtract(File.GetLastWriteTime("C:\yourPath\To\The\File.here")).TotalSeconds > 10 Then
    'do something'
End If

Edit: System.IO needs to be imported for this.

Answer 2

Investigate the FileSystemWatcher class. You should be able to keep track of the last time something changed, then use a timer to continuously check the difference in time.

Answer 3

Is it the file content that changes? If so you could hash the file content (or a selected snippet of it), then compare hash values every x seconds

Benefits of using this method is that you're not tied down by OS quirks (which FileSystemWatcher is full of) and wont have any issues if the file is updated twice in a second for example (which would be an issue if only monitoring the time the file changed).