c# 判断文件是否发生了变化

 {
            FileSystemWatcher watcher = new FileSystemWatcher();
            try
            {
                watcher.Path = @"d:\Test";
            }
            catch (ArgumentException e)
            {
                Console.WriteLine(e.Message);
                return;
            }
 
            //设置监视文件的哪些修改行为
            watcher.NotifyFilter = NotifyFilters.LastAccess
                | NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
 
 
            watcher.Filter = "*.txt";
 
            watcher.Changed += new FileSystemEventHandler(OnChanged);
            watcher.Created += new FileSystemEventHandler(OnChanged);
            watcher.Deleted += new FileSystemEventHandler(OnChanged);
            watcher.Renamed += new RenamedEventHandler(OnRenamed);
 
            watcher.EnableRaisingEvents = true;
 
            Console.WriteLine(@"Press 'q' to quit app.");
 
            while (Console.Read() != 'q');
        }
 
        static void OnChanged(object source, FileSystemEventArgs e)
        {
            Console.WriteLine("File：{0} {1}！", e.FullPath, e.ChangeType);
        }
 
        static void OnRenamed(object source, RenamedEventArgs e)
        {
            Console.WriteLine("File：{0} renamed to\n{1}", e.OldFullPath, e.FullPath);
        }