事件调用的一些小问题

Question

using System;
using System.Collections.Generic;
using System.Text;delegate void WorkStarted();
delegate void WorkProgressing();
delegate int WorkCompleted();class Worker
{
    public void DoWork()
    {
        Console.WriteLine("工作: 工作开始");
        if (started != null) started();        Console.WriteLine("工作: 工作进行中");
        if (progressing != null) progressing();
  
        Console.WriteLine("“工作: 工作完成”");
        if (completed != null)
        {
            foreach (WorkCompleted wc in completed.GetInvocationList())//GetInvocationList是啥啊？
            {
                wc.BeginInvoke(new AsyncCallback(WorkGraded), wc);//这句话啥意思？asynccallbakc是啥东西？
            }
        }    }    private void WorkGraded(IAsyncResult res) {
           WorkCompleted wc = (WorkCompleted)res.AsyncState;//这句话啥意思？res.AsyncState是啥意思？
           int grade = wc.EndInvoke(res);//这句话啥意思？
           Console.WriteLine("工人的工作得分＝" + grade);
       }
    public event WorkStarted started;
    public event WorkProgressing progressing;
    public event WorkCompleted completed;
}class Boss
{
 
    public int WorkCompleted()
    {
        System.Threading.Thread.Sleep(3000);
        Console.WriteLine("Better..."); return 6; /* 总分为10 */
    }
}class Universe
{
    static void WorkerStartedWork()
    {
        Console.WriteLine("Universe notices worker starting work");
    }   
    static int WorkerCompletedWork()
    {
        System.Threading.Thread.Sleep(4000);
        Console.WriteLine("Universe is pleased with worker's work");
        return 7;
    }    static void Main()
    {
                Worker peter = new Worker();
        Boss boss = new Boss();
        peter.completed += new WorkCompleted(boss.WorkCompleted);
        peter.started += new WorkStarted(Universe.WorkerStartedWork);
        peter.completed += new WorkCompleted(Universe.WorkerCompletedWork);        peter.DoWork();        Console.WriteLine("Main: 工人工作完成");
        Console.ReadLine();    }
}

Answer 1

using System;
using System.Collections.Generic;
using System.Text;delegate void WorkStarted();
delegate void WorkProgressing();
delegate int WorkCompleted();class Worker
{
public void DoWork()
{
Console.WriteLine("工作: 工作开始");
if (started != null) started(); Console.WriteLine("工作: 工作进行中");
if (progressing != null) progressing(); Console.WriteLine("“工作: 工作完成”");
if (completed != null)
{
foreach (WorkCompleted wc in completed.GetInvocationList())
//Delegate.GetInvocationList 方法 
//public virtual Delegate[] GetInvocationList()
//返回值：委托构成的数组，表示当前委托的调用列表。
{
wc.BeginInvoke(new AsyncCallback(WorkGraded), wc);
//异步调用wc这个代理，WorkGrade是回调函数，wc是传给回调函数的对象（类似与参数）
}
} } private void WorkGraded(IAsyncResult res)
{
WorkCompleted wc = (WorkCompleted)res.AsyncState;//回调函数接受调用函数传给他的对象，就是刚才的wc
int grade = wc.EndInvoke(res);//故名思议：结束调用
Console.WriteLine("工人的工作得分＝" + grade);
} public event WorkStarted started;
public event WorkProgressing progressing;
public event WorkCompleted completed;
}class Boss
{
public int WorkCompleted()
{
System.Threading.Thread.Sleep(3000);
Console.WriteLine("Better..."); return 6; /* 总分为10 */
}
}class Universe
{
static void WorkerStartedWork()
{
Console.WriteLine("Universe notices worker starting work");
}
static int WorkerCompletedWork()
{
System.Threading.Thread.Sleep(4000);
Console.WriteLine("Universe is pleased with worker's work");
return 7;
} static void Main()
{
Worker peter = new Worker();
Boss boss = new Boss();
peter.completed += new WorkCompleted(boss.WorkCompleted);
peter.started += new WorkStarted(Universe.WorkerStartedWork);
peter.completed += new WorkCompleted(Universe.WorkerCompletedWork); peter.DoWork(); Console.WriteLine("Main: 工人工作完成");
Console.ReadLine();
}
}