簡單的非同步編程入門例子

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace 非同步編程例子{    class Program    {        public delegate int CaculateDelegate(int min, int max);        static void Main(string[] args)        {            CaculateDelegate d=Caculate;            Console.WriteLine("請輸入:");            int min = int.Parse(Console.ReadLine());            Console.WriteLine("請輸入");            int max = int.Parse(Console.ReadLine());            IAsyncResult ret = d.BeginInvoke(min,max,null,null);            Console.WriteLine("正在計算中，請耐心等待.....");              while (!ret.IsCompleted)            {                Console.Write(".");                Thread.Sleep(1000);            }            int count = (int)d.EndInvoke(ret);            Console.WriteLine();            Console.WriteLine("{0}+{1}={2}",min,max,count);            Console.ReadKey();        }        public static int Caculate(int min, int max)        {            int count;            Thread.Sleep(5000);            count = min + max;            return count;        }    }}

上例使用輪詢方法不斷詢問非同步呼叫是否完成，會浪費不少CPU時間在迴圈等待上，下例可以讓非同步呼叫方法在結束時自動調用一個函數，並在這個函數中顯示處理結果。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;namespace 非同步編程例子{    class Program    {        public delegate int CaculateDelegate(int min, int max);        public static CaculateDelegate d = Caculate;        static void Main(string[] args)        {            Console.WriteLine("請輸入:");            int min = int.Parse(Console.ReadLine());            Console.WriteLine("請輸入");            int max = int.Parse(Console.ReadLine());            IAsyncResult ret = d.BeginInvoke(min,max,ShowResult,(min+","+max));            Console.WriteLine("正在計算中，請耐心等待.....");            Console.ReadKey();        }        public static int Caculate(int min, int max)        {            int count;            Thread.Sleep(5000);            count = min + max;            return count;        }        public static void ShowResult(IAsyncResult ret)        {            int count = (int)d.EndInvoke(ret);              string[] n = ((string)ret.AsyncState).Split(',');            Console.WriteLine();            Console.WriteLine("{0}+{1}={2}", n[0],n[1], count);        }    }}