使用BeginInvoke和EndInvoke进行异步调用的四种常用方法

使用BeginInvoke和EndInvoke进行异步调用的四种常用方法,每种方法都是通过BeginInvoke方法来启动异步方法，调用EndInvoke方法来完成异步调用。

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;

namespace ConsoleApplication1
{

    public delegate void AsynComputeCaller(int num, out int result);

    class Factorial
    {
        public int Compute(int num)
        {
            Thread.Sleep(new Random().Next(100,999));
            if (num == 1) return 1;

            return num * this.Compute(num - 1);
        }

        /// <summary>
        /// 异步计算阶乘
        /// </summary>
        /// <param name="num"></param>
        /// <param name="result"></param>
        public void AsynCompute(int num, out int result)
        {
            Console.WriteLine("\n   AsynCompute...start");

            DateTime startTime = DateTime.Now;
            result = this.Compute(num);
            DateTime endTime = DateTime.Now;

            Console.WriteLine("\n   AsynCompute...end(Milliseconds Used:{0})",
                endTime.Subtract(startTime).Milliseconds);
        }
    }

    class Program
    {
        int result = 0;

        /// <summary>
        /// 调用BeginInvoke方法启动异步方法，
        /// 进行某些操作，
        /// 然后调用EndInvoke方法来一直阻止请求线程到调用完成。
        /// </summary>
        void Run()
        {
            Factorial f = new Factorial();
            AsynComputeCaller caller = new AsynComputeCaller(f.AsynCompute);
            Console.WriteLine("Run...start");
            IAsyncResult iAsyncResult = caller.BeginInvoke(4, out result, null, null);
            //主线程进行一些操作
            Console.WriteLine("   主线程进行一些操作");
            for (int i = 0; i < 50; i++)
            {
                Thread.Sleep(50);
                Console.Write(".");
            }
            Console.WriteLine();
            //调用EndInvoke来等待异步调用结束，并获得结果
            caller.EndInvoke(out result, iAsyncResult);
            Console.Write("Run...end(result:{0})", result);
        }

        /// <summary>
        /// 调用BeginInvoke方法启动异步方法，
        /// 使用System.IAsyncResult.AsyncWaitHandle属性获取WaitHandle，
        /// 使用它的WaitOne方法一直阻止执行直到发出WaitHandle信号，
        /// 然后调用EndInvoke方法。
        /// </summary>
        void Run2()
        {
            Factorial f = new Factorial();
            AsynComputeCaller caller = new AsynComputeCaller(f.AsynCompute);
            Console.WriteLine("Run...start");
            IAsyncResult iAsyncResult = caller.BeginInvoke(12, out result, null, null);
            //主线程进行一些操作
            Console.WriteLine("   主线程进行一些操作");
            for (int i = 0; i < 50; i++)
            {
                Thread.Sleep(50);
                Console.Write(".");
            }
            Console.WriteLine();
            Console.WriteLine("   等待WaitHandle接收到信号");
            //等待WaitHandle接收到信号
            iAsyncResult.AsyncWaitHandle.WaitOne();
            caller.EndInvoke(out result, iAsyncResult);
            Console.Write("Run...end(result:{0})", result);
        }

        /// <summary>
        /// 调用BeginInvoke方法启动异步方法，
        /// 轮询由BeginInvoke返回的IAsyncResult，
        /// 确定异步调用何时完成，
        /// 然后调用EndInvoke。
        /// </summary>
        void Run3()
        {
            Factorial f = new Factorial();
            AsynComputeCaller caller = new AsynComputeCaller(f.AsynCompute);
            Console.WriteLine("Run...start");
            IAsyncResult iAsyncResult = caller.BeginInvoke(6, out result, null, null);
            //主线程进行一些操作
            Console.WriteLine("   主线程进行一些操作");
            while(!iAsyncResult.IsCompleted)
            {
                Thread.Sleep(100);
                Console.Write(".");
            }
            Console.WriteLine();
            Console.WriteLine("   异步方法已经结束");
            //等待WaitHandle接收到信号
            iAsyncResult.AsyncWaitHandle.WaitOne();
            caller.EndInvoke(out result, iAsyncResult);
            Console.Write("Run...end(result:{0})", result);
        }

        /// <summary>
        /// 调用BeginInvoke方法启动异步方法时，
        /// 将代表异步方法完成时需要回调的方法的委托传递给BeginInvoke。
        /// 异步调用完成后，将在ThreadPool线程上执行该回调方法。
        /// 在该回调方法中调用EndInvoke。
        /// </summary>
        void Run4()
        {
            Factorial f = new Factorial();
            AsynComputeCaller caller = new AsynComputeCaller(f.AsynCompute);
            Console.WriteLine("Run...start");
            IAsyncResult iAsyncResult = caller.BeginInvoke(6, out result,
                new AsyncCallback(CallbackMethod), caller);
            //主线程进行一些操作
            Console.WriteLine("   主线程进行一些操作");
            for (int i = 0; i < 50; i++)
            {
                Thread.Sleep(50);
                Console.Write(".");
            }
            Console.WriteLine();
            

        }

        void CallbackMethod(IAsyncResult ar)
        {
            AsynComputeCaller caller = (AsynComputeCaller)ar.AsyncState;
            caller.EndInvoke(out result, ar);
            Console.Write("Run...end(result:{0})", result);
        }

        static void Main(string[] args)
        {
            Program p = new Program();
            Console.WriteLine("\n\n*** Run ***");
            p.Run();

            Console.WriteLine("\n\n*** Run2 ***");
            p.Run2();

            Console.WriteLine("\n\n*** Run3 ***");
            p.Run3();

            Console.WriteLine("\n\n*** Run4 ***");
            p.Run4();
            Console.Read();
        }
    }
}