当需要监控某一文件，FileSystemWatcher类提供了Created, Deleted,Rename等事件。

就拿FileSystemWatcher的Created事件来说，该事件类型是FileSystemEventHandler。

public delgate void FileSystemEventHandler(Object sender, FileSystemEventArgs e)

○ sender表示事件的发起者
○ e表示事件参数

在C盘创建temp文件夹。

客户端。

    class Program
    {
        static void Main(string[] args)
        {
            var watcher = new FileSystemWatcher(@"c:\temp");
            watcher.EnableRaisingEvents = true; //启用FileSystemWatcher
            watcher.Created += new FileSystemEventHandler(OnCreated);
            watcher.Deleted += new FileSystemEventHandler(OnDeleted);
            watcher.Renamed += new RenamedEventHandler(OnRenamed);
            Console.ReadKey();
        }
        static void OnDeleted(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine("{0}:{1}", e.ChangeType, e.Name);
        }
        static void OnCreated(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine("{0}:{1}", e.ChangeType, e.Name);
        }
        static void OnRenamed(object sender, RenamedEventArgs e)
        {
            Console.WriteLine("{0}:原文件名{1},新文件名{2}", e.ChangeType, e.OldName, e.Name);
        }
    }

当然，可以通过 watcher.Renamed += OnCreated;注册事件。

C#监控文件夹变化