System.Threading.Mutex mutex;//注意，此变量要定义为成员变量，而不是局部变量

  bool CheckMultiInstance()
        {
            bool createdNew = true;

            mutex = new System.Threading.Mutex(true, "_TEST_Mutex_", out createdNew);//这种在系统多用户下，每个用户能启动一个程序进程。

mutex = new System.Threading.Mutex(true, "Global\\_TEST_Mutex_", out createdNew);//这种在系统中，不管几个用户，只能存在一个这样的程序进程

            if (!createdNew)
            {
               MessageBox.Show("Program is already running.");
            }
            return createdNew;
        }

        /// <summary>
        /// Is exist same process
        /// </summary>
        /// <returns></returns>
        public static Process GetExistProcess()
        {
            try
            {
                var current = Process.GetCurrentProcess();
                var pArrayy = System.Diagnostics.Process.GetProcessesByName(current.ProcessName);

                if (pArrayy == null || pArrayy.Length == 0)
                {
                    return null;
                }
                foreach (var item in pArrayy)
                {
                    try
                    {

                        if (!item.ProcessName.ToUpper().Contains(current.ProcessNameToUpper()))
                        {
                            continue;
                 &n