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();

}

}

}