c# multi-threaded logging - no locking

Question

I have created a Logging utility class for my multithreaded C# app. In order to ensure safe access to the file by all threads, I am locking on a static object as follows:

    private static readonly object locker = new object();

    public static void WriteLog(String message, params Object[] args)
    {
        try
        {
            string filename = m_baseDir + GetFilenameYYYMMDD("_LOG", ".log");
            lock (locker)
            {
                System.IO.StreamWriter sw = new System.IO.StreamWriter(filename, true);
                String msg = String.Format(message, args);
                sw.WriteLine(System.DateTime.Now.ToString() + " -" + msg);
                sw.Close();

            }
        }
        catch (Exception ex) { Console.WriteLine(ex); }
    }

However, when my application runs, I am still getting a System.IO.Exception on the line that initialises the sw variable.

System.IO.IOException: The process cannot access the file 'C:\\MyApp\\bin\\Debug\\Logs\\MyApp_2017_09_18_LOG.log' because it is being used by another process. at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)

I do get messages in the Log though, so some thread(s) must be able to write to the file.

How can I fix this so all threads can access the file?

Answer 1

I got the same problem like before:

I just use this:

        sw.Flush();
        sw.Close();

After the execution has done.

You can try this sw.Dispose(); also.

Hope it helps: