C# - Detect locked files in a directory

Question

I am looking for a way to watch a directory (and its sub-directories) for locked files i.e. when an application opens a file and locks it, an event should trigger in my app.

So far I have been using FileSystemWatcher for other purposes like detecting rename, update, etc. But watching lock [using last access] requires a registry tweak as specified Here which is not an option so far.

Other solution that I have thought so far is continuously look for change in 'LastAccess' attribute using FileInfo object from another thread and verify if the file is locked.

Is there a better solution?

I am not looking for a particular file. Here I have a directory and I need to watch for locking of file(s) in that directory. — Akshay Vats, Jun 06 '14 at 13:09
If you wanted to do this efficiently (and reliably) you would probably need to look at implementing your own [minifilter driver](http://msdn.microsoft.com/en-gb/library/windows/hardware/ff540402(v=vs.85).aspx) and hooking into the appropriate API. — James, Jun 06 '14 at 13:31

score 1 · Accepted Answer · answered Jun 06 '14 at 13:03

1

Unfortunately, there is no way to see if a file is locked by a process.

But you can always try yourself to access the file and fire an event based on that:

public bool IsFileLocked(string filePath)
{
    try
    {
        using (File.Open(filePath, FileMode.Open)){}
    }
    catch (IOException e)
    {
        retturn true;
    }  

    return false;
}

This function will return true when your application could not access the file (thus it's in use by another program), false otherwise.

answered Jun 06 '14 at 13:03

Complexity

5,682
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So your suggestion is to continuously attempt to open every file in the directory until you get an IOException? Terrible waste of resources. – James Jun 06 '14 at 13:05
Yes that's my last option. – Akshay Vats Jun 06 '14 at 13:05
@James I fear the same – Akshay Vats Jun 06 '14 at 13:06

score 0 · Answer 2 · edited May 23 '17 at 12:26

0

You can try to check handle.exe by Sysinternals, someone had similar question: Check for locked files in Directory and find locking applicaiton

I guess you might call this from your app.

edited May 23 '17 at 12:26

Community

1
1

answered Jun 06 '14 at 13:03

przmk

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C# - Detect locked files in a directory

2 Answers2