Notification when a file changes?

Question

Is there some mechanism by which I can be notified (in C#) when a file is modified on the disc?

Answer 1

You can use the FileSystemWatcher class.

public void CreateFileWatcher(string path) {     // Create a new FileSystemWatcher and set its properties.     FileSystemWatcher watcher = new FileSystemWatcher();     watcher.Path = path;     /* 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);      // 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); }  private static void OnRenamed(object source, RenamedEventArgs e) {     // Specify what is done when a file is renamed.     Console.WriteLine("File: {0} renamed to {1}", e.OldFullPath, e.FullPath); }