c#异步，（无回调函数）

using System;namespace ConsoleApplication1{    class Class1    {        //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 = 1;            while (i < 1000)            {                i = i + 1;                Console.WriteLine("Event2 " + i.ToString());            }            Console.WriteLine("Event2 End");        }        [STAThread]        static void Main(string[] args)        {            long start = 0;            long end = 0;            Class1 c = new Class1();            Console.WriteLine("ready");            start = DateTime.Now.Ticks;            //实例委托            AsyncEventHandler asy = new AsyncEventHandler(c.Event1);            //异步调用开始，没有回调函数和AsyncState,都为null            IAsyncResult ia = asy.BeginInvoke(null, null);            //同步开始，            c.Event2();            //异步结束，若没有结束，一直阻塞到调用完成，在此返回该函数的return，若有返回值。            asy.EndInvoke(ia);            //都同步的情况。            //c.Event1();            //c.Event2();            end = DateTime.Now.Ticks;            Console.WriteLine("时间刻度差=" + Convert.ToString(end - start));            Console.ReadLine();        }    }}