线程安全：
class Program

    {

        public delegate void MyDelegate(string aa);

        static void Main(string[] args)

        {

            MyDelegate dele = new MyDelegate(LockTest);

            MyDelegate dele1 = new MyDelegate(LockTest);

            dele.BeginInvoke("aa", null,null);

            dele1.BeginInvoke("aa", null, null);

            Console.ReadKey();

        }

        private static void LockTest(string aa)

        {

            string thisServiceLock = string.Intern(aa+"_lockCheck");

            lock (thisServiceLock)

            {

                Console.WriteLine("线程ID" + Thread.CurrentThread.ManagedThreadId.ToString());

                Thread.Sleep();

                Console.WriteLine("线程ID" + Thread.CurrentThread.ManagedThreadId.ToString());

            }

        }

    }