如何通过.NET判断文件是否已更改？

我正在寻找一种方法来确定特定文件何时更改,通过.NET.(我最终想要的是在文件发生变化后立即复制文件的功能.)如何做到这一点？

您可以使用FileSystemWatcher对象.这会引发指定监视文件夹中文件更改的事件.

class Program
    {
        static void Main(string[] args)
        {
            FileSystemWatcher fsw = new FileSystemWatcher(@"c:\temp");
            fsw.Changed += new FileSystemEventHandler(fsw_Changed);
            fsw.Deleted += new FileSystemEventHandler(fsw_Deleted);
            fsw.Renamed += new RenamedEventHandler(fsw_Renamed);
            fsw.Created += new FileSystemEventHandler(fsw_Created);
            fsw.EnableRaisingEvents = true;
            Console.ReadLine();
        }

        static void fsw_Created(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine("{0} was created", e.FullPath);
        }

        static void fsw_Renamed(object sender, RenamedEventArgs e)
        {
            Console.WriteLine("{0} was Renamed", e.FullPath);
        }

        static void fsw_Deleted(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine("{0} was Deleted", e.FullPath);
        }

        static void fsw_Changed(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine("{0} was Changed", e.FullPath);
        }
}