Filesystemwatcher does not raise rename event handler in C# on Windows7

Question

Hello,

I am using C# 3.5 on Windows 7.

We have implemented a program with a FileSystemWatcher.

Here, rename event is not get raised. But, it is working on a few systems.

What can be doable in such scenario?

Answer 1

There may be a timing window in your code such that not all filesystem events are properly captured on all your systems. Can you post it?

It is a 'feature' of the underlying Win32 API ReadDirectoryChangesW and hence FileSystemWatcher that under heavy load, events can get missed. There are mitigation suggestions in the MSDN docs.

Answer 2

Make sure that you set your watcher:

fileSystemWatcher.EnableRaisingEvents = true;

Answer 3

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Globalization; using System.IO; using System.Linq; using System.Security.AccessControl; using System.Security.Permissions; using System.Text; using System.Windows.Forms;

namespace Watcher { public partial class Form1 : Form { public Form1() { InitializeComponent(); FileRenamed();

    }
    private static string _osLanguage = null;
    [PermissionSet(SecurityAction.Demand, Name = "FullTrust")] 

    private void FileRenamed()
    {
        MessageBox.Show("Code is Started Now");
        // Create a new FileSystemWatcher and set its properties.
        FileSystemWatcher watcher = new FileSystemWatcher();

        SetDirectoryAccess(@"c:\temp");

        watcher.Path = @"C:\Temp";

        /* Watch for changes in LastAccess and LastWrite times, and
           the renaming of files or directories. */
        watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
           | NotifyFilters.FileName | NotifyFilters.DirectoryName;

        // Only watch text files.
        watcher.Filter = "*.txt";

        // Add event handlers.
        watcher.Changed += new FileSystemEventHandler(OnChanged);
        watcher.Created += new FileSystemEventHandler(OnChanged);
        watcher.Deleted += new FileSystemEventHandler(OnChanged);
        watcher.Renamed += new RenamedEventHandler(OnRenamed);
        watcher.Error += new ErrorEventHandler(OnError);

        // Begin watching.
        watcher.EnableRaisingEvents = true;

    }

    // Define the event handlers.
    private static void OnChanged(object source, FileSystemEventArgs e)
    {
        // Specify what is done when a file is changed, created, or deleted.
        //Console.WriteLine("File: " + e.FullPath + " " + e.ChangeType);
        MessageBox.Show("Something is changed in the File");
    }

    private static void OnRenamed(object source, RenamedEventArgs e)
    {
        // Specify what is done when a file is renamed.
        MessageBox.Show("File Is Renamed");
        //WatcherChangeTypes wct = e.ChangeType;
        //Console.WriteLine("File {0} {2} to {1}", e.OldFullPath, e.FullPath, wct.ToString());
    }


    //  This method is called when the FileSystemWatcher detects an error.
    private static void OnError(object source, ErrorEventArgs e)
    {
        MessageBox.Show("Error Trapped");
        //  Show that an error has been detected.
        Console.WriteLine("The FileSystemWatcher has detected an error");
        //  Give more information if the error is due to an internal buffer overflow.
        if (e.GetException().GetType() == typeof(InternalBufferOverflowException))
        {
            //  This can happen if Windows is reporting many file system events quickly 
            //  and internal buffer of the  FileSystemWatcher is not large enough to handle this
            //  rate of events. The InternalBufferOverflowException error informs the application
            //  that some of the file system events are being lost.
            Console.WriteLine(("The file system watcher experienced an internal buffer overflow: " + e.GetException().Message));
        }
    }


    private void button1_Click(object sender, EventArgs e)
    {
        //File.Move(@"\\NAS\dossier_echange\Carl\temp\Test.txt", @"\\NAS\dossier_echange\Carl\temp\Test007.txt"); 
        File.Move(@"c:\temp\Test.txt", @"c:\temp\Test007.txt"); 
    }

    internal static void SetDirectoryAccess(string directoryPathString)
    {
        string everyoneString;

        if (OSLanguage.Equals("en-US"))
            everyoneString = "Everyone";
        else
            everyoneString = "Tout le monde";

        //sets the directory access permissions for everyone
        DirectorySecurity fileSecurity = Directory.GetAccessControl(directoryPathString);
        //creates the access rule for directory
        fileSecurity.ResetAccessRule(new FileSystemAccessRule(everyoneString, FileSystemRights.FullControl, AccessControlType.Allow));
        //sets the access rules for directory
        Directory.SetAccessControl(directoryPathString, fileSecurity);
    }

    public static string OSLanguage
    {
        get
        {
            if (_osLanguage == null)
                _osLanguage = CultureInfo.CurrentCulture.Name;

            return _osLanguage;
        }
        set
        {
            _osLanguage = value;
        }
    }
}

}