异步(BeginInvoke,EndInvoke)

整个异步调用过程中都是围绕IAsyncResult来进行的,,BeginXXX 返回这个对象,EndXXX接收这个对象来结束当前异步对象

public interface IAsyncResult
{
     WaitHandle AsyncWaitHandle { get; } //阻塞一个线程，直到一个或多个同步对象接收到信号
     Boolean IsCompleted { get; } //判读当前异步是否完成
     Object AsyncState { get; } //获取额外的参数值
     Boolean CompletedSynchronously { get; } //几乎没有使用
 }

 

 public class AsyncResult : IAsyncResult, IMessageSink
 {
       //IAsyncResult 的实现      
       public virtual WaitHandle AsyncWaitHandle { get; }
       public virtual bool IsCompleted { get; }
       public virtual object AsyncState { get; }
       public virtual bool CompletedSynchronously { get; }
 
       // 其他一些重要的属性
       public bool EndInvokeCalled { get; set; } //检验是否调用了EndInvoke()
       public virtual object AsyncDelegate { get; } //获取原始的委托对象
}

 

 

ar.AsyncWaitHandle.WaitOne() //阻碍当前线程,直到异步调用结束. 

 

namespace ConsoleApplication15
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("[(#{1}){0}]:Asynchronous Start", DateTime.Now.ToString(), Thread.CurrentThread.ManagedThreadId);

            AsyncTest test = new AsyncTest();
            ConsoleApplication15.AsyncTest.SalaryEventHandler del = test.YearlySalary;
            //使用回调函数
            AsyncCallback callback = new AsyncCallback(OnSalaryCallback);
            IAsyncResult ar = del.BeginInvoke(100000, 15, 100000, callback, 2000);

            DoAntherJob();
            Console.ReadLine(); // 让黑屏等待,不会直接关闭..
        }

        //开始其他工作.
        static void DoAntherJob()
        {
            Thread.Sleep(1000);//需要1秒才能完成这个工作,注1
            Console.WriteLine("[(#{1}){0}]:Do Another Job", DateTime.Now.ToString(), Thread.CurrentThread.ManagedThreadId);
        }

        static void OnSalaryCallback(IAsyncResult asyncResult)
        {
            //通过AsyncState 获取额外的参数.
            decimal para = (int)asyncResult.AsyncState;

            //通过AsyncDelegate 获取原始的委托对象
            AsyncResult obj = (AsyncResult)asyncResult;
            ConsoleApplication15.AsyncTest.SalaryEventHandler del = (ConsoleApplication15.AsyncTest.SalaryEventHandler)obj.AsyncDelegate;

            if (asyncResult.IsCompleted)// 判读是否已经调用完成
                Console.WriteLine("[(#{1}){0}]:Asynchronous Finished.", DateTime.Now.ToString(), Thread.CurrentThread.ManagedThreadId);

            decimal val = del.EndInvoke(asyncResult);

            Console.WriteLine("[(#{2}){0}]:Output Result:{1}", DateTime.Now.ToString(), val + para, Thread.CurrentThread.ManagedThreadId);
        }
    }

    public class AsyncTest
    {
        public delegate decimal SalaryEventHandler(decimal salary, int monthCount, decimal bonus); // 对应YearlySalary方法
        public decimal YearlySalary(decimal salary, int monthCount, decimal bonus)
        {
            //模拟耗时/复杂的逻辑计算.
            Thread.Sleep(3000);//等待3秒,注2
            return salary * monthCount + bonus;
        }
    }
}