How do I find out which process is locking a file using .NET?

Question

I\'ve seen several of answers about using Handle or Process Monitor, but I would like to be able to find out in my own code (C#) which process is locking a file.

I ha

Answer 1

I had issues with stefan's solution. Below is a modified version which seems to work well.

using System;
using System.Collections;
using System.Diagnostics;
using System.Management;
using System.IO;

static class Module1
{
    static internal ArrayList myProcessArray = new ArrayList();
    private static Process myProcess;

    public static void Main()
    {
        string strFile = "c:\\windows\\system32\\msi.dll";
        ArrayList a = getFileProcesses(strFile);
        foreach (Process p in a)
        {
            Debug.Print(p.ProcessName);
        }
    }

    private static ArrayList getFileProcesses(string strFile)
    {
        myProcessArray.Clear();
        Process[] processes = Process.GetProcesses();
        int i = 0;
        for (i = 0; i <= processes.GetUpperBound(0) - 1; i++)
        {
            myProcess = processes[i];
            //if (!myProcess.HasExited) //This will cause an "Access is denied" error
            if (myProcess.Threads.Count > 0)
            {
                try
                {
                    ProcessModuleCollection modules = myProcess.Modules;
                    int j = 0;
                    for (j = 0; j <= modules.Count - 1; j++)
                    {
                        if ((modules[j].FileName.ToLower().CompareTo(strFile.ToLower()) == 0))
                        {
                            myProcessArray.Add(myProcess);
                            break;
                            // TODO: might not be correct. Was : Exit For
                        }
                    }
                }
                catch (Exception exception)
                {
                    //MsgBox(("Error : " & exception.Message)) 
                }
            }
        }

        return myProcessArray;
    }
}

UPDATE

If you just want to know which process(es) are locking a particular DLL, you can execute and parse the output of tasklist /m YourDllName.dll. Works on Windows XP and later. See

What does this do? tasklist /m "mscor*"