Using C#, how does one figure out what process locked a file?

Question

In Windows, how do I determine (using C#) what process locked a file?

Third-party tools are helpful, but not what I\'m looking for.

Answer 1

I rewrote the GetProcessesLockingFile() method in the solution. The code was not working.

For example, you have a folder "C:\folder1\folder2" and a process in folder2 (process1). If the process was running, GetProcessesLockingFile() was returning "C:\folder1\folder2". So the condition if (files.Contains(filePath)) => if ("C:\folder1\folder2".contains("C:\folder1\folder2\process1")) was never true.

So this is my solution:

public static List GetProcessesLockingFile(FileInfo file)
{
    var procs = new List();

    var processListSnapshot = Process.GetProcesses();
    foreach (var process in processListSnapshot)
    {
        if (process.Id <= 4) { continue; } // system processes

        List paths = GetFilesLockedBy(process);
        foreach (string path in paths)
        {
            string pathDirectory = path;
            if (!pathDirectory.EndsWith(Constants.DOUBLE_BACKSLASH))
            {
                pathDirectory = pathDirectory + Constants.DOUBLE_BACKSLASH;
            }
            string lastFolderName = Path.GetFileName(Path.GetDirectoryName(pathDirectory));

            if (file.FullName.Contains(lastFolderName))
            {
                procs.Add(process);
            }
        }
    }
    return procs;
}

Or with a string parameter:

public static List GetProcessesLockingFile(string filePath)
{
    var procs = new List();

    var processListSnapshot = Process.GetProcesses();
    foreach (var process in processListSnapshot)
    {
        if (process.Id <= 4) { continue; } // system processes

        List paths = GetFilesLockedBy(process);
        foreach (string path in paths)
        {
            string pathDirectory = path;
            if (!pathDirectory.EndsWith(Constants.DOUBLE_BACKSLASH))
            {
                pathDirectory = pathDirectory + Constants.DOUBLE_BACKSLASH;
            }
            string lastFolderName = Path.GetFileName(Path.GetDirectoryName(pathDirectory));

            if (filePath.Contains(lastFolderName))
            {
                procs.Add(process);
            }
        }
    }
    return procs;
}