using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.IO;using System.Runtime.Serialization.Formatters.Binary;using System.Xml;using System.Threading; namespace ConsoleApplication1{    class Program    {        static void Main(string[] args)        {            Console.WriteLine("Client application is starting!");            Thread.CurrentThread.Name = "Main Thread";            Cal cal = new Cal();            AddDelegate del = new AddDelegate(cal.Add);             // 需要保存 IAsyncResult 对象以便后边条用EndInvoke方法时作参数传递            IAsyncResult asyncResult = del.BeginInvoke(5, 6, null, null);             // 做某些其它的事情，模拟需要执行 3 秒钟            for (int i = 1; i <= 3; i++)            {                Thread.Sleep(TimeSpan.FromSeconds(i));                Console.WriteLine("{0}: Client executed {1} second(s).", Thread.CurrentThread.Name, i);            }             // 传递 IAsyncResult 对象            int rtnVal = del.EndInvoke(asyncResult);            Console.WriteLine("Result: {0}\n", rtnVal);             Console.WriteLine("\nPress any key to exit...");            Console.ReadLine();         }         public delegate int AddDelegate(int a, int b);         public class Cal        {            public int Add(int a, int b)            {                if (Thread.CurrentThread.IsThreadPoolThread)                {                    Thread.CurrentThread.Name = "Pool Thread";                }                Console.WriteLine("Method invoked!");                 // 做某些其它的事情，模拟需要执行 2 秒钟                for (int i = 0; i < 2; i++)                {                    Thread.Sleep(TimeSpan.FromSeconds(1));                    Console.WriteLine("{0}: Add executed {1} second(s).", Thread.CurrentThread.Name, i);                }                Console.WriteLine("Method complete!");                return a + b;            }        }    }}