c# windows service 实现监控其他程序是否被关闭,关闭则报警

namespace MonitorService
{
    public partial class MonitorSv : ServiceBase
    {
        string AppName = "",MusicName = "";
        string apppath = "";
        Thread threadwork;
        SoundPlayer player;
        public MonitorSv()
        {
            InitializeComponent();
            string path = Directory.GetCurrentDirectory()+"\Resources\XML\AppFile.xml";// Directory.GetCurrentDirectory() + "\Resources\XML\AppFile.xml";
            string[] names = RwXmlBs.ReadXml(path);
            if (names != null && names.Length == 2)
            this.AppName = names[0];
            this.MusicName = names[1];
            //Beep(1000, 10000);//调试可以响,但是安装后不响,所以改成播放声音

            //WriteFile(names[0] + "<=>" + names[1] + "++path:" + path, 0, "构造函数");
            PlayMusic();

        }

        private void PlayMusic()
        {
            if (String.IsNullOrEmpty(MusicName))
                return;
            player = new SoundPlayer();
            player.SoundLocation = @"D:\spring.wav";// MusicName;// @""+ MusicName + "";
            player.Load(); //同步加载声音  
            player.Play(); //启用新线程播放           
        }

        private void PlayerStop()
        {
            if (player != null)
            {
                player.Stop();
            }
        }
        protected override void OnStart(string[] args)
        {
            if (threadwork == null)
            {
                threadwork = new Thread(CheckAppMethod);
                threadwork.IsBackground = true;
                threadwork.Start();
            }
        }

        private void CheckAppMethod()
        {
            Process[] ps = null;
            try
            {
                while (true)
                {
                    if (!String.IsNullOrEmpty(AppName))
                    {
                        ps = Process.GetProcessesByName(AppName); // "MakeCard"); //不用带.exe
                        if (ps.Length <= 0)//进程被杀死,则报警.
                        {
                            PlayMusic();
                            //Been(500,1000);//不可以响,搞不懂
                        }
                        else
                        {
                            PlayerStop();
                        }
                    }
                    System.Threading.Thread.Sleep(5000);
                }
            }
            catch (Exception EX)
            {
                WriteFile(AppName, ps.Length, "异常的"+EX.ToString());
                OnShutdown();
            }
        }

        private void WriteFile(string AppName,int Length, string EX)
        {
            try
            {
                FileStream fs = new FileStream(apppath+"\CloseFileLog.txt", FileMode.OpenOrCreate, FileAccess.Write);
                StreamWriter sw = new StreamWriter(fs);
                sw.BaseStream.Seek(0, SeekOrigin.End);
                sw.WriteLine("AppName:" + AppName + "++ps.Length:" + Length + ">>>" + DateTime.Now.ToString() + EX.ToString() + "
");
                sw.Flush();
                sw.Close();
                fs.Close();
            }
            catch (Exception ex)
            {

            }
        }

        protected override void OnShutdown()
        {
            base.OnShutdown();
        }

        protected override void OnStop()
        {
            GC.Collect();
            PlayerStop();
        }

        // 第一个参数是指频率的高低，越大越高，第二个参数是指响的时间多长  
     [DllImport("kernel32.dll", EntryPoint = "Beep")]      
     public static extern int Beep(int dwFreq,int dwDuration);
    }
}