Find which processes are using the file.

If you go back to my second post in this thread, you'll see that I suggested that the CodePlex code should be compiled to a dll as I thought this would be easier to deal with.

However, you could try embedding it directly in your project if that would be preferable to you.

I assume you've added a reference to the dll to your project.

Have you remembered to add the using directive as well?

using VmcController.Services;

My suggestion would be to try and use one of the approaches mentioned in the StackOverflow thread.

The most promising is to compile the code in this link to a dll:

http://vmccontroller.codeplex.com/SourceControl/changeset/view/47386#195318 

and then call:

DetectOpenFiles.GetOpenFilesEnumerator(processID);

However, when I tried this on my Windows 7 64-bit machine, it was unable to detect any open files even for MS Word and I think the problem may lie with the NtQuerySystemInformation function which (if you google it) doesn't seem to work properly on 64 bit systems though there's no mention of this is in the documentation itself:

http://msdn.microsoft.com/en-us/library/windows/desktop/ms724509(v=vs.85).aspx 

Here's my test code:

using System;
using System.Diagnostics;
using System.Collections.Generic;
using VmcController.Services;
using System.IO;

class Test
{
    static void Main()
    {
        Process[] procs = Process.GetProcessesByName("winword");

        if (procs.Length > 0)
        {
           int id = procs[0].Id;
           IEnumerator fie = DetectOpenFiles.GetOpenFilesEnumerator(id);
  
           while(fie.MoveNext())
           {
              Console.WriteLine(fie.Current.FullName);
           }
        }

        Console.ReadKey();
    }
}

It's very difficult to do something like this from C#.

See my answer to this thread:

http://www.c-sharpcorner.com/Forums/Thread/167694/application-path.aspx 

and check also this SO thread:

http://stackoverflow.com/questions/177146/how-do-i-get-the-list-of-open-file-handles-by-process-in-c