IAsyncResult 接口

IAsyncResult 接口由包含可异步操作的方法的类实现。它是启动异步操作的方法的返回类型，如 FileStream.BeginRead，也是结束异步操作的方法的第三个参数的类型，如 FileStream.EndRead。当异步操作完成时，IAsyncResult 对象也将传递给由 AsyncCallback 委托调用的方法。

支持 IAsyncResult 接口的对象存储异步操作的状态信息，并提供同步对象以允许线程在操作完成时终止。

有关如何使用 IAsyncResult 接口的详细说明，请参见“使用异步方式调用同步方法”主题。

using System;

using System.Threading;

using System.Runtime.Remoting;

using System.Runtime.Remoting.Contexts;

using System.Runtime.Remoting.Messaging;

//

// Context-Bound type with Synchronization Context Attribute

//

[Synchronization()]

public class SampleSyncronized : ContextBoundObject

{

    // A method that does some work - returns the square of the given number

    public int Square(int i)

    {

        Console.Write("SampleSyncronized.Square called.  ");

        Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode());

        return i*i;

    }

}

//

// Async delegate used to call a method with this signature asynchronously

//

public delegate int SampSyncSqrDelegate(int i);

//Main sample class

public class AsyncResultSample

{

    public static void Main()

    {

        int callParameter = ;

        int callResult = ;

        //Create an instance of a context-bound type SampleSynchronized

        //Because SampleSynchronized is context-bound, the object sampSyncObj

        //is a transparent proxy

        SampleSyncronized sampSyncObj = new SampleSyncronized();

        //call the method synchronously

        Console.Write("Making a synchronous call on the object.  ");

        Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode());

        callParameter = ;

        callResult = sampSyncObj.Square(callParameter);

        Console.WriteLine("Result of calling sampSyncObj.Square with {0} is {1}.\n\n", callParameter, callResult);

        //call the method asynchronously

        Console.Write("Making an asynchronous call on the object.  ");

        Console.WriteLine("The hash of the current thread is: {0}", Thread.CurrentThread.GetHashCode());

        SampSyncSqrDelegate sampleDelegate = new SampSyncSqrDelegate(sampSyncObj.Square);

        callParameter = ;

        IAsyncResult aResult = sampleDelegate.BeginInvoke(callParameter, null, null);

        //Wait for the call to complete

        aResult.AsyncWaitHandle.WaitOne();

        callResult = sampleDelegate.EndInvoke(aResult);

        Console.WriteLine("Result of calling sampSyncObj.Square with {0} is {1}.", callParameter, callResult);

    }

}