如何防止wpf程序异常关闭，守护进程是暂时能想到的最好方式。最好是能够一次编码就把守护进程的事情做完。

思路：程序打开时，首先打开守护进程；由守护进程打开主程序；守护进程与主程序间互相守护，任何一个挂了都能自动重启。

实现：Mutex互斥量，守护进程和主程序分别使用不同的互斥量，既可以防止重复打开软件，又可以检测程序是否在运行。

话不多说，直接上代码：

    /// <summary>
    /// App.xaml 的交互逻辑
    /// </summary>
    public partial class App : Application
    {
        /// <summary>
        /// 主进程互斥量
        /// </summary>
        private static System.Threading.Mutex mutex_main;

        /// <summary>
        /// 守护进程互斥量
        /// </summary>
        private static System.Threading.Mutex mutex_deamon;

        /// <summary>
        /// 是否为主进程
        /// </summary>
        private static bool isMain = false;

        /// <summary>
        /// 打开监视定时器
        /// </summary>
        public void RunMonitorTimer()
        {
            System.Timers.Timer timer = new System.Timers.Timer();
            timer.Elapsed += timer_Elapsed;
            timer.Interval = 2000;
            timer.Start();
        }

        /// <summary>
        /// 打开程序
        /// </summary>
        /// <param name="arg">参数不为null时打开主进程，否则打开守护进程</param>
        public void RunProcess(string arg = null)
        {
            /* 运行程序，不带参数，打开守护进程 */
            Process m_Process = new Process();
            m_Process.StartInfo.FileName = Process.GetCurrentProcess().MainModule.FileName;
            m_Process.StartInfo.Arguments = arg;
            m_Process.Start();
        }

        protected override void OnStartup(StartupEventArgs e)
        {
            //根据参数判断开启主进程还是守护进程，守护进程不带参数，主进程带参数
            if (e.Args.Length < 1)
            {
                Application.Current.ShutdownMode = System.Windows.ShutdownMode.OnExplicitShutdown;

                //守护进程互斥量
                mutex_deamon = new System.Threading.Mutex(true, "MUTEX_DEAMON");
                if (mutex_deamon.WaitOne(0, false))
                {
                    RunMonitorTimer();

                    // 显示一个自定义窗体，非主窗体，用于阻塞进程，窗体关闭后，守护进程将关闭
                    WndDeamon wnd = new WndDeamon();
                    wnd.ShowDialog();

                    this.Shutdown();
                }
                else
                {
                    MessageBox.Show("程序已经在运行！", "提示");
                    this.Shutdown();
                }
            }
            else
            {
                isMain = true;
                mutex_main = new System.Threading.Mutex(true, "MUTEX_MAIN");
                if (mutex_main.WaitOne(0, false))
                {
                    RunMonitorTimer();

                    base.OnStartup(e);
                    Application.Current.ShutdownMode = ShutdownMode.OnMainWindowClose;
                }
                else
                {
                    Application.Current.ShutdownMode = System.Windows.ShutdownMode.OnExplicitShutdown;
                    MessageBox.Show("程序已经在运行！", "提示");
                    this.Shutdown();
                }
            }
        }

        void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            if (!isMain)
            {
                if (mutex_main == null)
                {
                    mutex_main = new System.Threading.Mutex(true, "MUTEX_MAIN");
                }
                if (mutex_main.WaitOne(0, false))
                {
                    //必须释放mutex，否则将导致mutex被占用，主程序不能允许
                    mutex_main.Dispose();
                    mutex_main = null;

                    RunProcess("main");
                }
            }
            else
            {
                if (mutex_deamon == null)
                {
                    mutex_deamon = new System.Threading.Mutex(true, "MUTEX_DEAMON");
                }
                if (mutex_deamon.WaitOne(0, false))
                {
                    mutex_deamon.Dispose();
                    mutex_deamon = null;

                    RunProcess();
                }
            }
        }
    }