C# 异步

 class Invoke
    {
        #region 异步不带返回值
        //声明委托
        public delegate void AsyncEventHandler();

        //异步方法
        void Event1()
        {
            Console.WriteLine("Event1 Start!");
            System.Threading.Thread.Sleep(4000);
            Console.WriteLine("Event1 End!");
        }

        //同步方法
        void Event2()
        {
            Console.WriteLine("Event2 Start!");
            int i = 0;
            while (i < 20)
            {
                i = i + 1;
                Console.WriteLine("Event2...."+i.ToString());
            }
            Console.WriteLine("Event2 End!");
        }

        public void Show()
        {
            long start = 0;
            long end = 0;
            Console.WriteLine("Ready");
            start = DateTime.Now.Ticks;
            //实例化委托
            AsyncEventHandler asy = new AsyncEventHandler(Event1);
            //异步调用开始，没有回调函数和AsyState，都为null
            IAsyncResult ia=asy.BeginInvoke(null,null);
            //同步方法开始
            Event2();
            //异步结束，若没有结束，一直阻塞到调用完成，在此返回值函数的return，若有返回值，
            asy.EndInvoke(ia);

            end = DateTime.Now.Ticks;
            Console.WriteLine("时间刻度差："+Convert.ToString(end-start));

            Console.ReadLine();


        }
        #endregion

        #region 异步带返回值

        private string MethodName(int num, out int retNum)
        {
            retNum = num;
            return "Hell";
        }

        private delegate string invokeDelegate(int num, out int retNum);

        public void Run()
        {
            invokeDelegate del = new invokeDelegate(MethodName);

            int i;

            IAsyncResult iar = del.BeginInvoke(525,out i,null,null);

            //去做别的事情

            string result = del.EndInvoke(out i,iar);
            Console.WriteLine(i.ToString() + "____" + result);
        }
        #endregion
    }