本文出自：https://www.cnblogs.com/2186009311CFF/p/10024949.html

在App.xaml.cs填充一下內容，即可實現只允許一個執行，且不解鎖螢幕的情況下，重啟執行。

 public partial class App : Application
    {
        System.Threading.Mutex mutex;
        public App()
        {
            this.Startup += new StartupEventHandler(App_Startup);
            this
 
.DispatcherUnhandledException += new DispatcherUnhandledExceptionEventHandler(Application_DispatcherUnhandledException);
            AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);
        }
        private void App_Startup(object sender, StartupEventArgs e)
        {
            
 
bool ret;
            mutex = new System.Threading.Mutex(true, "TestEXEName", out ret);

            if (!ret)
            {
                MessageBox.Show("已有一個客戶端正在執行,請先結束原來客戶端!");
                Environment.Exit(0);
            }
            #region 設定程式開機自動執行(+登錄檔項)
            try
            {
                SetSelfStarting(
 
true, "TestEXEName.exe");
            }
            catch (Exception ex)
            {
                WriteLog(ex);
            }
            
            #endregion

        }
        private void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
        {
            if (e.ExceptionObject is Exception)
                WriteLog(e.ExceptionObject);
            else
                WriteLog(e);
        }

        private void Application_DispatcherUnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)
        {
            if (e.Exception is Exception)
                WriteLog(e.Exception);
            else
                WriteLog(e);
        }

        #region 登錄檔開機自啟動


        /// <summary>
        /// 開機自動啟動
        /// </summary>
        /// <param name="started">設定開機啟動，或取消開機啟動</param>
        /// <param name="exeName">登錄檔中的名稱</param>
        /// <returns>開啟或停用是否成功</returns>
        public bool SetSelfStarting(bool started, string exeName)
        {
            RegistryKey key = null;
            try
            {

                string exeDir = System.Windows.Forms.Application.ExecutablePath;
                //RegistryKey HKLM = Registry.CurrentUser;
                //key = Registry.LocalMachine.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true);//開啟登錄檔子項
                key = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true);//開啟登錄檔子項

                if (key == null)//如果該項不存在的話，則建立該子項
                {
                    key = Registry.LocalMachine.CreateSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run");
                }
                if (started)
                {
                    try
                    {
                        object ob = key.GetValue(exeName, -1);

                        if (!ob.ToString().Equals(exeDir))
                        {
                            if (!ob.ToString().Equals("-1"))
                            {
                                key.DeleteValue(exeName);//取消開機啟動
                            }
                            key.SetValue(exeName, exeDir);//設定為開機啟動
                        }
                        key.Close();

                    }
                    catch (Exception ex)
                    {
                        WriteLog(ex);
                        return false;
                    }
                }
                else
                {
                    try
                    {
                        key.DeleteValue(exeName);//取消開機啟動
                        key.Close();
                    }
                    catch (Exception ex)
                    {
                        WriteLog(ex);
                        return false;
                    }
                }
                return true;
            }
            catch (Exception ex)
            {
                WriteLog(ex);
                if (key != null)
                {
                    key.Close();
                }
                return false;
            }
        }

        #endregion

        private  void WriteLog(object exception)
        {
            Exception ex = exception as Exception;

            using (FileStream fs = File.Open(".//ErrorLog.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                fs.Seek(0, SeekOrigin.End);
                byte[] buffer = Encoding.Default.GetBytes("-------------------------------------------------------\r\n");
                fs.Write(buffer, 0, buffer.Length);

                buffer = Encoding.Default.GetBytes(DateTime.Now.ToString() + "\r\n");
                fs.Write(buffer, 0, buffer.Length);

                if (ex != null)
                {
                    buffer = Encoding.Default.GetBytes("成員名: " + ex.TargetSite + "\r\n");
                    fs.Write(buffer, 0, buffer.Length);

                    buffer = Encoding.Default.GetBytes("引發異常的類: " + ex.TargetSite.DeclaringType + "\r\n");
                    fs.Write(buffer, 0, buffer.Length);

                    buffer = Encoding.Default.GetBytes("異常資訊: " + ex.Message + "\r\n");
                    fs.Write(buffer, 0, buffer.Length);

                    buffer = Encoding.Default.GetBytes("引發異常的程式集或物件: " + ex.Source + "\r\n");
                    fs.Write(buffer, 0, buffer.Length);

                    buffer = Encoding.Default.GetBytes("棧：" + ex.StackTrace + "\r\n");
                    fs.Write(buffer, 0, buffer.Length);
                }
                else
                {
                    buffer = Encoding.Default.GetBytes("應用程式錯誤: " + exception.ToString() + "\r\n");
                    fs.Write(buffer, 0, buffer.Length);
                }
            }

        }
    }

參考：https://bbs.csdn.net/topics/390951628?page=1

https://www.cnblogs.com/gaobing/p/gaobing.html