如何在C＃中编写文件系统观察器？

| 我已经使用C＃编写了一个小型应用程序，其中涉及Filesystemwather来监视特定的文件夹。一旦文件被更新，它将打开一个串行端口并将文件内容写入该串行端口。但是有时文件不会在4-5个小时内更新。而且似乎filesystemwatcher进入睡眠状态，并且在文件更新后没有响应。这是我的代码：

FileSystemWatcher watcher = new FileSystemWatcher();

watcher.Path = @\"Z:\\\";
watcher.EnableRaisingEvents = true;
watcher.NotifyFilter = NotifyFilters.LastAccess;

watcher.Filter = \"*.wsx\";
watcher.Changed += new FileSystemEventHandler(OnChanged);

Console.WriteLine(\"Press \\\'q\\\' to quit the sample.\");
while (Console.Read() != \'q\') ;

public static string CrL = \"\\r\\n\";

private static void OnChanged(object source, FileSystemEventArgs e)
{
    string FileName;
    FileName = e.FullPath;

    Console.WriteLine(\"File: \" + e.FullPath + \" \" + e.ChangeType);
    Console.WriteLine(\"FILE is changed 1\");
    SerialPort port = new SerialPort(\"COM1\");

    port.Encoding = Encoding.ASCII;
    port.Open();

    using (System.IO.TextReader reader = System.IO.File.OpenText(e.FullPath))
    {
        string line;
        while ((line = reader.ReadLine()) != null)
        {
            port.Write(line);
            port.Write(CrL);
        }
    }

    port.Close();

    Console.WriteLine(\"FILE is sent to com port\");
}

关于这一点的任何指针。