委托和事件,睡前故事
分类:web前端

作者:Chris Sells
译者:荣耀
【译注:C#晋级小说。Chris Sells是《ATL Internals》一书我之一。译文中全部程
序调节和测量检验环境均为Microsoft Visual Studio.NET 7.0 Beta2和 Microsoft .NET Framewo
rk SDK Beta2。代码正是文章,请紧凑翻阅代码J】
获取具备结果
     今后,peter终于松了一口气。他曾经设法满足了独具的监听者,而且不会和一定
落实一体耦合。但是,他又在乎到即使boss和universe都为办事打了分,但她只获得了
三个打分。【译注:请参见上节例子代码及译注】他希望能收获每一个监听者的评分结
果。由此,他调整提取委托调用列表,以便手工业分别调用它们:
public void DoWork()
{
//...
Console.WriteLine("Worker: work completed",',',');
     if( completed != null)
{
foreach( WorkCompleted wc in completed.GetInvocationList())
{
int grade = wc(,',',');
Console.WriteLine("Worker grade= " + grade,',',');
}
}
}
【译注:以下是本节描述之完好代码示例:
using System;
delegate void WorkStarted(,',',');
delegate void WorkProgressing(,',',');
delegate int WorkCompleted(,',',');
class Worker
{
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( started != null ) started(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( progressing != null ) progressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
        if( completed != null)
        {
            foreach( WorkCompleted wc in completed.GetInvocationList())
            {
                int grade = wc(,',',');
                Console.WriteLine("Worker grade= " + grade,',',');
            }
        }
     }
     public event WorkStarted started ;
     public event WorkProgressing progressing;
     public event WorkCompleted completed;
}
class Boss
{
     public int WorkCompleted()
     {
          Console.WriteLine("Better...",',',');
         return 4; /* out of 10 */
     }
}
class Universe
{
     static void WorkerStartedWork()
     {
          Console.WriteLine("Universe notices worker starting work",',',');
     }
     static int WorkerCompletedWork()
     {
          Console.WriteLine("Universe 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: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*
以下是上段前后相继输出结果:
Worker: work started
Universe notices worker starting work
Worker: work progressing
Worker: work completed
Better...
Worker grade = 4 【译注:boss打地铁4分也博得啦J】
Universe pleased with worker's work
Worker grade = 7
Main: worker completed work
*/

异步文告:触发和忽略
不料,boss和universe被其他什么事纠葛上了,那就代表他们给peter打分的时辰被延
迟了:
class Boss
{
public int WorkCompleted()
{
System.Threading.Thread.Sleep(3000,',',');
             Console.WriteLine("Better...",',',');
return 6; /* out of 10 */
}
}
class Universe
{
static int WorkerCompletedWork()
{
System.Threading.Thread.Sleep(4000,',',');
Console.WriteLine("Universe is pleased with worker's work",',',');
return 7;
    }
    //...
}
而倒霉的是,由于peter是同时通报boss和universe并等待她们打分的,这个重临评分的
公告今后看来要占用他重重行事时间,由此,peter决定忽视评分何况异步触发事件:
public void DoWork()
{
//...
Console.WriteLine("Worker: work completed",',',');
         if( completed != null )
{
foreach( WorkCompleted wc in completed.GetInvocationList())
{
wc.BeginInvoke(null, null,',',');
}
}
}
【译注:下边给出本节例子完整代码:
using System;
delegate void WorkStarted(,',',');
delegate void WorkProgressing(,',',');
delegate int WorkCompleted(,',',');
class Worker
{
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( started != null ) started(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( progressing != null ) progressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
        if( completed != null )
        {
            foreach( WorkCompleted wc in completed.GetInvocationList())
            {
                wc.BeginInvoke(null, null,',',');
            }
        }
     }
     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; /* out of 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: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*
以下是上段程序输出结果:
Worker: work started
Universe notices worker starting work
Worker: work progressing
Worker: work completed
Main: worker completed work //【译注:由于是异步触发事件,因而这一行先输出啦
J】
Better... //【译注:评分已被忽视】
Universe pleased with worker's work //【译注:评分已被忽视】
*/

异步通告:轮询
     那就使得peter能够文告监听者的同临时候和煦也能立即回到职业,让进度的线程池调
用委托。不过不久他就意识监听者对其工作的评分废弃了。【译注:请参见上节例子代
码及译注】peter知道她做了一件明智的事并乐意universe作为一个完全(不单单是他的
boss)评判她。因而,peter异步触发事件,但为期轮询,以考查可以得到的评分:
public void DoWork()
{
//...
Console.WriteLine("Worker: work completed",',',');
if( completed != null )
{
foreach( WorkCompleted wc in completed.GetInvocationList() )
{
IAsyncResult res = wc.BeginInvoke(null, null,',',');
while( !res.IsCompleted ) System.Threading.Thread.Sleep(1,',',');
int grade = wc.EndInvoke(res,',',');
Console.WriteLine("Worker grade= " + grade,',',');
}
}
}
【译注:上边给出本节例子完整代码:
using System;
delegate void WorkStarted(,',',');
delegate void WorkProgressing(,',',');
delegate int WorkCompleted(,',',');
class Worker
{
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( started != null ) started(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( progressing != null ) progressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
        if( completed != null )
        {
            foreach( WorkCompleted wc in completed.GetInvocationList() )
            {
                IAsyncResult res = wc.BeginInvoke(null, null,',',');
                while( !res.IsCompleted ) System.Threading.Thread.Sleep(1,',',');
                int grade = wc.EndInvoke(res,',',');
                Console.WriteLine("Worker grade= " + 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; /* out of 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: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*
以下是上段前后相继输出结果:
Worker: work started
Universe notices worker starting work
Worker: work progressing
Worker: work completed
Better...
Worker grade = 6
Universe pleased with worker's work
Worker grade = 7
Main: worker completed work //【译注:注意这些结果到终极才输出,下一节首句意
思正是如此】
*/

异步布告:委托
     不幸的是,peter又倒退了—就象他一初步想制止boss站在边上面监视她相近。也
说是,他今后要监看整个工作进程。【译注:请参见上节示例输出结果的申明】由此
,peter决定选用自个儿的嘱托作为异步委托完结时的打招呼情势,那样他就足以立刻回去工
作,而当工作被打分时,还是能够接过通报:
public void DoWork()
{
//...
Console.WriteLine("Worker: work completed",',',');
if( completed != null )
{
foreach( WorkCompleted wc in completed.GetInvocationList() )
{
wc.BeginInvoke(new AsyncCallback(WorkGraded), wc,',',');
}
}
}
private void WorkGraded(IAsyncResult res)
{
WorkCompleted wc = (WorkCompleted)res.AsyncState;
int grade = wc.EndInvoke(res,',',');
Console.WriteLine("Worker grade= " + grade,',',');
}
【译注:上边给出本节例子完整代码:
using System;
delegate void WorkStarted(,',',');
delegate void WorkProgressing(,',',');
delegate int WorkCompleted(,',',');
class Worker
{
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( started != null ) started(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( progressing != null ) progressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
        if( completed != null )
        {
            foreach( WorkCompleted wc in completed.GetInvocationList() )
            {
                wc.BeginInvoke(new AsyncCallback(WorkGraded), wc,',',');
            }
        }
     }
    private void WorkGraded(IAsyncResult res)
    {
        WorkCompleted wc = (WorkCompleted)res.AsyncState;
        int grade = wc.EndInvoke(res,',',');
        Console.WriteLine("Worker grade= " + 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; /* out of 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: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*以下是上段程序输出结果:
Worker: work started
Universe notices worker starting work
Worker: work progressing
Worker: work completed
Main: worker completed work //【译注:异步委托产生了效果,因而这一行先输出啦
J】
Better...
Worker grade = 6
Universe pleased with worker's work
Worker grade = 7
*/

同乐乐
     peter、boss和universe最后都满足了。boss和universe都能够仅被通报其感兴趣
的风浪,并削减了贯彻上的承负和不须求的来回来去调用。peter能够布告他们每一位,而
不用管供给多久手艺从那多少个目的措施中回到,并还是能异步获得评分结果。pete
r知道做到那或多或少并不太轻易,因为出于是异步触发事件,目的措施就有望运维在另一
个线程里,就好像上节示例同样。然则,peter[J]和mike[J]是好对象,而mike明白线程问
题并可提供该领域的指点。
     从今今后,他们都很高兴J
-全文完- 

委托和事件— 叁个伪造的传说 收藏此页到茶秀网摘
作者: 荣耀   www.ASPCool.com 时间:贰零零叁-11-16 中午 02:56:11  阅读次数:5570 

作者:Chris Sells
译者:荣耀
【译注:C#进级小说。Chris Sells是《ATL Internals》一书作者之一。译文中所有程
序调节和测验遭逢均为Microsoft Visual Studio.NET 7.0 Beta2和 Microsoft .NET Framewo
rk SDK Beta2。代码就是作品,请留神阅读代码J】
种类耦合
既往,在南方的二个国外,有一个叫peter的费劲的工友。他对boss唯唯诺诺,但她
的boss却是个卑鄙无信的小丑,他持有始有终必要peter不断陈诉专业情状。由于peter不愿意
被boss瞅着专业,于是她向boss承诺任何时候汇报职业进程。peter利用类型援用定时回调b
oss来达成这一个承诺:
using System;//【译注:译者补充】
class Worker
{
     public void Advise(Boss boss)
{
_boss = boss;
}
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( _boss != null ) _boss.WorkStarted(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( _boss != null ) _boss.WorkProgressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
          if( _boss != null )
         {
              int grade = _boss.WorkCompleted(,',',');
              Console.WriteLine("Worker grade = " + grade,',',');
         }
     }
     private Boss _boss;
}
class Boss
{
     public void WorkStarted() { /*boss不关心. */ }
     public void WorkProgressing() { /*boss不关心. */ }
     public int WorkCompleted()
     {
          Console.WriteLine("It's about time!",',',');
         return 2; /* out of 10 */
     }
}
class Universe
{
     static void Main()
     {
         Worker peter = new Worker(,',',');
         Boss boss = new Boss(,',',');
          peter.Advise(boss,',',');
          peter.DoWork(,',',');
          Console.WriteLine("Main: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*【译注:以下是上段前后相继输出结果:
Worker: work started
Worker: work progressing
Worker: work completed
It's about time!
Worker grade = 2
Main: worker completed work
】*/
接口
     今后,peter成了二个特有人物,他非但能够经受卑鄙的boss,和universe也树立
了严密的沟通。peter感到universe对他的工作经过相通感兴趣。不幸的是,除了保险b
oss能够被通报外,若是不为universe增多一个非常的打招呼方法和回调,peter不可能向un
iverse公告其行事历程。Peter希望能从那三个通告方法的实现中分别出地下的照拂约定,
为此,他操纵将艺术剥离到接口中:
using System; //【译注:译者补充】
interface IWorker伊夫nts //【译注:那正是抽离出来的接口】
{
     void WorkStarted(,',',');
     void WorkProgressing(,',',');
     int WorkCompleted(,',',');
}
class Worker
{
     public void Advise(IWorker伊夫nts events卡塔尔国//【译注:现在传递的参数类型为
接口引用】
{
_events = events;
}
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( _events != null ) _events.WorkStarted(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if(_events != null ) _events.WorkProgressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
          if(_events != null )
         {
int grade = _events.WorkCompleted(,',',');
              Console.WriteLine("Worker grade = " + grade,',',');
         }
     }
     private IWorkerEvents _events;
}
class Boss : IWorkerEvents //【译注:Boss完结该接口】
{
     public void WorkStarted(){ /*boss不关心. */ }
     public void WorkProgressing(){ /*boss不关心. */ }
     public int WorkCompleted()
     {
          Console.WriteLine("It's about time!",',',');
         return 3; /* out of 10 */
     }
}
class Universe
{
     static void Main()
     {
         Worker peter = new Worker(,',',');
         Boss boss = new Boss(,',',');
          peter.Advise(boss,',','); //【译注:或peter.Advise((IWorkerEvents)boss,',',');

          peter.DoWork(,',',');
          Console.WriteLine("Main: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*【译注:以下是上段前后相继输出结果:
Worker: work started
Worker: work progressing
Worker: work completed
It's about time!
Worker grade = 3
Main: worker completed work
】*/
委托
     不幸的是,由于peter忙于布告boss完毕这些接口,以至于未有顾得上通知univer
se也完成该接口,但他领略不久就需如此,最少,他一度悬空了对boss的引用,因而,
其余完毕了IworkerEvents接口的哪个人都足以接过专门的事业进度公告。【译注:请参见上一
节代码示例及译注】
     不过,peter的boss依旧最为不满,“Peter!”boss咆哮者,“你干什么要通告本人
何以时候初始职业、几时正在进展工作?笔者不尊敬这一个事件,你不唯有逼迫笔者达成那
些方法,你还浪费了你的爱抚的行事时间等自己从事件中回到。当自家实现的点子需占用很
长日龙时,你等自己的大运也要大大延长!你难道不能够思索别的方式不要老是来烦作者吗?

     此时,peter意识到固然在无数处境下接口很有用,但在处总管件时,接口的粒度
还缺乏精巧。他还要能做到仅仅布告监听者真正感兴趣的风云。因而,peter决定把接口
里的方法肢解成几何个单身的嘱托函数,每一个都好象是独有三个方法的小接口。
using System; //【译注:译者补充】
delegate void WorkStarted(,',',');
delegate void WorkProgressing(,',',');
delegate int WorkCompleted(,',',');
class Worker
{
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( started != null ) started(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( progressing != null ) progressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
          if( completed != null )
         {
              int grade = completed(,',',');
              Console.WriteLine("Worker grade = " + grade,',',');
         }
     }
     public WorkStarted started; //【译注:这样写更规矩:public WorkStarted
started = null;】
     public WorkProgressing progressing; //【译注:这样写更规矩:public Work
Progressing progressing = null;】
     public WorkCompleted completed; //【译注:那样写更规矩:public WorkComp
leted completed = null;】
}
class Boss
{
     public int WorkCompleted()
     {
          Console.WriteLine("Better...",',',');
         return 4; /* out of 10 */
     }
}
class Universe
{
     static void Main()
     {
         Worker  peter = new Worker(,',',');
         Boss boss = new Boss(,',',');
          peter.completed = new WorkCompleted(boss.WorkCompleted,',',');
          peter.DoWork(,',',');
          Console.WriteLine("Main: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*【译注:以下是上段程序输出结果:
Worker: work started
Worker: work progressing
Worker: work completed
Better...
Worker grade = 4
Main: worker completed work

*/
【译注:对“但在处监护人件时,接口的粒度还相当不足精细”的明白可用下例表达,请紧密
观测一下前后相继,思考一下这样做的不利之处J
using System;
interface IWorkStartedEvent
{
     void WorkStarted(,',',');
}
interface IWorkProgressingEvent
{
     void WorkProgressing(,',',');
}
interface IWorkCompletedEvent
{
     int WorkCompleted(,',',');
}
class Worker
{
public void Advise(IWorkCompletedEvent AEvent)
{
_event = AEvent;
}
    public void DoWork()
    {
        Console.WriteLine("Worker: work completed",',',');
        if(_event != null )
         {
            int grade = _event.WorkCompleted(,',',');
            Console.WriteLine("Worker grade = " + grade,',',');
        }
    }
    private IWorkCompletedEvent _event;
}
class Boss : IWorkCompletedEvent
{
public int WorkCompleted()
{
Console.WriteLine("Better...",',',');
        return 4; /* out of 10 */
    }
}
class Universe
{
static void Main()
     {
         Worker peter = new Worker(,',',');
         Boss boss = new Boss(,',',');
          peter.Advise(boss,',',');
          peter.DoWork(,',',');
          Console.WriteLine("Main: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*以下是上段前后相继输出结果:
Worker: work completed
Better...
Worker grade = 4
Main: worker completed work
*/

静态监听者
     那就高达了不要boss不爱慕的事件去烦他的对象。可是,peter依旧不能够使univ
erse成为其监听者。因为universe是一个全封闭的实业,所以将委托挂钩在universe的
实例上不妥的(虚构一下Universe的多少个实例需求有个别能源...)。peter意识到应将委
托关系于universe的静态成员上,因为委托也完全适应于静态成员:
using System;
delegate void WorkStarted(,',',');
delegate void WorkProgressing(,',',');
delegate int WorkCompleted(,',',');
class Worker
{
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( started != null ) started(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( progressing != null ) progressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
          if( completed != null )
         {
              int grade = completed(,',',');
              Console.WriteLine("Worker grade= " + grade,',',');
         }
     }
     public WorkStarted started = null;
     public WorkProgressing progressing = null;
     public WorkCompleted completed = null;
}
class Boss
{
     public int WorkCompleted()
     {
          Console.WriteLine("Better...",',',');
         return 4; /* out of 10 */
     }
}
//【译注:以上代码为翻译补充】
class Universe
{
    static void WorkerStartedWork()
    {
        Console.WriteLine("Universe notices worker starting work",',',');
    }
    static int WorkerCompletedWork()
    {
        Console.WriteLine("Universe pleased with worker's work",',',');
        return 7;
    }
    static void Main()
    {
        Worker peter = new Worker(,',',');
        Boss boss = new Boss(,',',');
        peter.completed = new WorkCompleted(boss.WorkCompleted,',','); //【译注:×

        peter.started = new WorkStarted(Universe.WorkerStartedWork,',',');
        peter.completed = new WorkCompleted(Universe.WorkerCompletedWork,',',');//
【译注:这一行代码使得“×”那一行代码白做了L】
        peter.DoWork(,',',');
        Console.WriteLine("Main: worker completed work",',',');
        Console.ReadLine(,',',');
    }
}
/*【译注:以下是上段程序输出结果:
Worker: work started
Universe notices worker starting work
Worker: work progressing
Worker: work completed
Universe pleased with worker's work
Worker grade = 7
Main: worker completed work
】*/
事件
     不幸的是,universe今后变得太忙况兼不习于旧贯于注意某一位—universe用本人的
信托代表了peter的boss的寄托,那明明是将Worker类的寄托字段设为public的意外的副
职能。【译注:请参见上节例子代码及译注】雷同地,要是peter的boss不耐性了,他自
己就足以触发peter的委托(peter的boss不过有暴力趋向的)
// peter的boss自个儿出手了
if( peter.completed != null ) peter.completed(,',',');
peter希望确定保障不会时有发生那二种情景。他意识到必得为每二个委托参加注册和反注册函数
,那样监听者就足以加上或移去它们,但哪个人都无法清空整个事件列表。peter自个儿没去
得以实现那几个措施,相反,他使用event关键字让C#编写翻译器帮她达到那么些目标:
class Worker
{
//...
public event WorkStarted started;
    public event WorkProgressing progressing;
    public event WorkCompleted completed;
}
     peter驾驭关键字event使得委托具有这样的风味:只允许C#客商用+=或-=操作符添
加或移去它们自个儿,那样就反逼boss和universe举止名贵一些:
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: worker completed work",',',');
Console.ReadLine(,',',');
}
【译注:以下是欧洲经济共同体代码:
using System;
delegate void WorkStarted(,',',');
delegate void WorkProgressing(,',',');
delegate int WorkCompleted(,',',');
class Worker
{
     public void DoWork()
     {
          Console.WriteLine("Worker: work started",',',');
          if( started != null ) started(,',',');
          Console.WriteLine("Worker: work progressing",',',');
          if( progressing != null ) progressing(,',',');
          Console.WriteLine("Worker: work completed",',',');
          if( completed != null )
         {
              int grade = completed(,',',');
              Console.WriteLine("Worker grade = " + grade,',',');
         }
     }
    public event WorkStarted started ;
    public event WorkProgressing progressing;
    public event WorkCompleted completed;
}
class Boss
{
     public int WorkCompleted()
     {
          Console.WriteLine("Better...",',',');
         return 4; /* out of 10 */
     }
}
class Universe
{
     static void WorkerStartedWork()
     {
          Console.WriteLine("Universe notices worker starting work",',',');
     }
     static int WorkerCompletedWork()
     {
          Console.WriteLine("Universe pleased with worker's work",',',');
         return 7;
     }
     static void Main()
     {
         Worker peter = new Worker(,',',');
         Boss boss = new Boss(,',',');
        peter.completed += new WorkCompleted(boss.WorkCompleted,',','); //【译注:
√】
        peter.started += new WorkStarted(Universe.WorkerStartedWork,',',');
        peter.completed += new WorkCompleted(Universe.WorkerCompletedWork,',',');
          peter.DoWork(,',',');
          Console.WriteLine("Main: worker completed work",',',');
          Console.ReadLine(,',',');
     }
}
/*

葡萄牙共和国语版最初的著小编:克莉丝Sells(www.sellsbrothers.com)
翻译:袁晓辉(www.farproc.com )
原稿地址:

 
  
   
 
     
  本文章摘要自人民邮电书局出版的《Windows Forms程序设计》(ChrisSells著,荣耀、蒋贤哲译)。通过一个呼天抢地的虚构轶闻解释了C#/.NET中央委员托和事件的机制和接纳。
  
  1 委托
  
  早前,在南方的三个外国,有二个叫Peter的努力的工友,他对CEO(boss)男娼女盗,但是他的boss却是个卑鄙多疑的玩意,他坚持不懈供给Peter不断汇报专门的学问进展。由于Peter不期待被boss瞧着办事,于是他向boss承诺任何时候陈说专门的学问进程。彼得通过如下所示的类型化的引用(typed reference)准时回调boss来落实那么些承诺:
  
  class Worker {
   public void Advise(Boss boss) {this.boss = boss; }
   public void DoWork() {
   Console.WriteLine("Worker: work started");
   if( boss != null ) boss.WorkStarted();
  
   Console.WriteLine("Worker: work progressing");
   if( boss != null ) boss.WorkProgressing();
  
   Console.WriteLine("Worker: work completed");
   if( boss != null ) {
   int grade = boss.WorkCompleted();
   Console.WriteLine("Worker grade= " + grade);
   }
   }
   Boss boss;
  }
  
  class Boss {
   public void WorkStarted() {/* boss不关心 */ }
   public void WorkProgressing() {/* boss不关心 */ }
   public int WorkCompleted() {
   Console.WriteLine("It's about time!");
   return 2; /* 10分以内 */
   }
  }
  
  class Universe {
   static void Main() {
   Worker peter = new Worker();
   Boss boss = new Boss();
   peter.Advise(boss);
   peter.DoWork();
  
   Console.WriteLine("Main: worker completed work");
   Console.ReadLine();
   }
  }
  
  1.1 接口
  
  现在,Peter成了三个特有人物,他不但能够经受卑鄙的boss,和四周的社会风气(universe)也树立了严峻的联络。Peter以为universe对他的办事历程相仿感兴趣。不幸的是,借使不为universe增加多少个不相同通常的Advise方法和特别的回调,除了作保boss能够被通告外,彼得并无法向universe文告职业进程。Peter希望能从这些公告方法的贯彻中分离出秘密的布告列表,为此,他垄断将艺术分别到二个接口中:
  
  interface IWorkerEvents {
   void WorkStarted();
   void WorkProgressing();
   int WorkCompleted();
  }
  
  class Worker {
   public void Advise(IWorkerEvents events) {this.events = events; }
   public void DoWork() {
   Console.WriteLine("Worker: work started");
   if( events != null ) events.WorkStarted();
  
   Console.WriteLine("Worker: work progressing");
   if(events != null ) events.WorkProgressing();
  
   Console.WriteLine("Worker: work completed");
   if(events != null ) {
   int grade = events.WorkCompleted();
   Console.WriteLine("Worker grade= " + grade);
   }
   }
   IWorkerEvents events;
  }
  
  class Boss : IWorkerEvents {
   public void WorkStarted() {/* boss不关心 */ }
   public void WorkProgressing() {/* boss不关心 */ }
   public int WorkCompleted() {
   Console.WriteLine("It's about time!");
   return 3; /* 10分以内 */
   }
  }
  
  1.2 委托
  
  不幸的是,由于Peter忙于说性格很顽强在困难重重或巨大压力面前不屈boss达成那么些接口,以致于未有顾得上文告universe也落到实处该接口,但她希望尽量做到这或多或少,最少他曾经悬空了对boss的引用,由此,别的完毕了IWorker伊夫nts接口的如何人也能够获得专门的学业进程通知。
  
  不过, Peter的boss还是特别不满。“Peter!”boss咆哮者,“你干吗要公告自身哪些时候初叶专门的学问、几时正值张开专门的学业?作者不爱抚这么些事件,你不唯有免强作者完成那一个点子,你还浪费了你的谈何轻便的干活时间等本身从事件中回到。当本身的完毕必要占用十分短日羊时,你等笔者的时间也要大大延长!你难道不能够思虑别的格局不要老是来烦小编啊?”
  
  因而,Peter意识到即使在不菲景色下接口很有用,但在处监护人件时,接口的粒度还相当不足精巧。他希望能成功仅仅文告监听者真正感兴趣的风浪。为此,彼得决定把接口中的方法分解为多少个单身的寄托函数,每一个都好象是只包涵二个艺术的微型接口:
  
  delegate void WorkStarted();
  delegate void WorkProgressing();
  delegate int WorkCompleted();
  
  class Worker {
   public void DoWork() {
   Console.WriteLine("Worker: work started");
   if( started != null ) started();
  
   Console.WriteLine("Worker: work progressing");
   if( progressing != null ) progressing();
  
   Console.WriteLine("Worker: work completed");
   if( completed != null ) {
   int grade = completed();
   Console.WriteLine("Worker grade= " + grade);
   }
   }
   public WorkStarted started;
   public WorkProgressing progressing;
   public WorkCompleted completed;
  }
  
  class Boss {
   public int WorkCompleted() {
   Console.WriteLine("Better...");
   return 4; /* 10分以内 */
   }
  }
  
  class Universe {
   static void Main() {
   Worker peter = new Worker();
   Boss boss = new Boss();
  
   // 注意:大家已将Advise方法替换为赋值运算符
   peter.completed = new WorkCompleted(boss.WorkCompleted);
   peter.DoWork();
   Console.WriteLine("Main: worker completed work");
   Console.ReadLine();
   }
  }
  
  1.3 静态订阅者
  
  利用委托,Peter达到了不拿boss不关怀的平地风波去烦他的靶子,可是Peter还是不可能使universe成为其订阅者之一。因为universe是一个全密闭的实业,所以将委托挂钩在实例成员上不妥的(虚构一下Universe的多个实例要求有个别能源)。相反,彼得需求将委托挂钩到静态成员上,因为委托也统统扶持静态成员:
  
  class Universe {
   static void WorkerStartedWork() {
   Console.WriteLine("Universe notices worker starting work");
   }
  
   static int WorkerCompletedWork() {
   Console.WriteLine("Universe pleased with worker's work");
   return 7;
   }
  
   static void Main() {
   Worker peter = new Worker();
   Boss boss = new Boss();
  
   // 注意:在下边包车型地铁三行代码中,
   // 使用赋值运算符不是叁个好习贯,
   // 请接着读下去,以便通晓增多委托的不利方法。
   peter.completed = new WorkCompleted(boss.WorkCompleted);
   peter.started = new WorkStarted(Universe.WorkerStartedWork);
   peter.completed = new WorkCompleted(Universe.WorkerCompletedWork);
   peter.DoWork();
  
   Console.WriteLine("Main: worker completed work");
   Console.ReadLine();
   }
  }
  
  2 事件
  
  不幸的是,由于universe今后变得太忙并且不习贯于注意某壹人,universe已经设法用自个儿的寄托代表了Peter的boss的委托,那明显是将Worker类的委托字段设为public而诱致的意外的副功用。相像,即使Peter的boss不耐性了,他和睦就能够触发彼得的寄托(Peter的boss可是有强力倾向的)
  
  // Peter的boss本身决定总体
  if( peter.completed != null ) peter.completed();
  
  Peter希望确定保障不会发生这两种情形。他意识到必得为每叁个委托参预注册和反注册函数,那样订阅者就足以增加或移去它们本人,但何人都不能够清空整个事件列表只怕触发它的风云。peter自身没去完毕这个办法,相反,他接纳event关键字让C#编写翻译器帮他创设那些情势:
  
  class Worker {
  ...
   public event WorkStarted started;
   public event WorkProgressing progressing;
   public event WorkCompleted completed;
  }
  
  Peter晓得event关键字使委托具有如此的品质:只同意C#顾客用+=或-=操作符增多或移去它们本身,那样就勉强boss和universe举止崇高一些:
  
  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: worker completed work");
   Console.ReadLine();
  }
  
  2.1 获取具备结果
  
  至此,Peter终于松了一口气。他一度设法满意了具备订阅者的急需,并且不会和特定完成一体耦合。但是,他又在意到即便boss和universe都为他的做事打了分,但她只得到了一个打分。在有三个订阅者的图景下,Peter希望能博得全体订阅者的评分结果。因而,他调控“步向委托”,提取订阅者列表,以便手工分别调用它们:
  
  public void DoWork() {
   ...
   Console.WriteLine("Worker: work completed");
   if( completed != null ) {
   foreach( WorkCompleted wc in completed.GetInvocationList() ) {
   int grade = wc();
   Console.WriteLine("Worker grade= " + grade);
   }
   }
  }
  
  2.2 异步公告:触发和忽略
  
  不料,在这里期间,boss和universe被其余什么事郁结上了,那就意味着她们给Peter的办事打分的时间被大大延长了:
  
  class Boss {
   public int WorkCompleted() {
   System.Threading.Thread.Sleep(3000);
   Console.WriteLine("Better..."); return 6; /* 10分以内 */
   }
  }
  
  class Universe {
   static int WorkerCompletedWork() {
   System.Threading.Thread.Sleep(4000);
   Console.WriteLine("Universe is pleased with worker's work");
   return 7;
   }
   ...
  }
  
  不幸的是,由于Peter是还要通报每叁个订阅者并等候她们打分的,那些要求再次来到评分的关照以往看来要占用他重重办事时间,因而,Peter决定忽视评分并且异步触发事件:
  
  public void DoWork() {
   ...
   Console.WriteLine("Worker: work completed");
   if( completed != null ) {
   foreach( WorkCompleted wc in completed.GetInvocationList() ) {
   wc.BeginInvoke(null, null);
   }
   }
  }
  
  2.3 异步通告:轮询
  
  那几个聪明的小把戏允许Peter在文告订阅者的同时能顿时赶回事业,让进程的线程池调用委托。不过没过多久Peter就意识订阅者给她的打分被搞丢了。他理解本身干活儿做得不错,并乐意universe作为三个完好(而不只是她的boss)称誉他。由此,Peter异步触发事件,但为期轮询,以便察看能够获得的评分:
  
  public void DoWork() {
   ...
   Console.WriteLine("Worker: work completed");
   if( completed != null ) {
   foreach( WorkCompleted wc in completed.GetInvocationList() ) {
   IAsyncResult res = wc.BeginInvoke(null, null);
   while( !res.IsCompleted ) System.Threading.Thread.Sleep(1);
   int grade = wc.EndInvoke(res);
   Console.WriteLine("Worker grade= " + grade);
   }
   }
  }
  
  2.4 异步公告:委托
  
  不幸的是,Peter又赶回了难点的源点,就疑似她一开头期望防止boss站在边上面监视他干活同样。由此,Peter决定动用另贰个信托作为异步专门的职业做届期的布告方式,那样他就能够马上赶回工作,而当工作被打分时,如故能够摄取通报:
  
  public void DoWork() {
   ...
   Console.WriteLine("Worker: work completed");
   if( completed != null ) {
   foreach( WorkCompleted wc in completed.GetInvocationList() ) {
   wc.BeginInvoke(new AsyncCallback(WorkGraded), wc);
   }
   }
  }
  
  void WorkGraded(IAsyncResult res) {
   WorkCompleted wc = (WorkCompleted)res.AsyncState;
   int grade = wc.EndInvoke(res);
   Console.WriteLine("Worker grade= " + grade);
  }
  
  3 普天同乐
  
  Peter、boss和universe最后都乐意了。boss和universe都得以仅被通报其感兴趣的轩然大波,并压缩了落到实处的担任和无需的来回调用。Peter能够通报他们每一人,而不必管需求多久手艺从这么些指标措施中回到,并还是能够异步取得评分结果。结果获得如下完整的消除方案:
  
  delegate void WorkStarted();
  delegate void WorkProgressing();
  delegate int WorkCompleted();
  
  class Worker {
   public void DoWork() {
   Console.WriteLine("Worker: work started");
   if( started != null ) started();
  
   Console.WriteLine("Worker: work progressing");
   if( progressing != null ) progressing();
  
   Console.WriteLine("Worker: work completed");
   if( completed != null ) {
  
   foreach( WorkCompleted wc in completed.GetInvocationList() ) {
   wc.BeginInvoke(new AsyncCallback(WorkGraded), wc);
   }
   }
   }
  
   void WorkGraded(IAsyncResult res) {
   WorkCompleted wc = (WorkCompleted)res.AsyncState;
   int grade = wc.EndInvoke(res);
   Console.WriteLine("Worker grade= " + 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; /* 10分以内 */
   }
  }
  
  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: worker completed work");
   Console.ReadLine();
   }
  }
  
  Peter到消息道异步获取结果会带给一些难题。由于异步触发事件,所以目的措施有异常的大可能率施行于另三个线程中,就如Peter的“目的措施几时完结”的打招呼那样。不过,彼得熟识第14章“多线程客商分界面”,因而,他掌握在营造WinForms应用程序时怎么去管理此类难点。
  
  从今将来,他们直白过得都极高兴。  

以下是上段前后相继输出结果:
Worker: work started
Universe notices worker starting work
Worker: work progressing
Worker: work completed
Better...// 【译注:boss也通报到啦J“√”那一行代码有用啊J,可是且慢,boss打
的那4分未有得到,前边只得到了Universe给的7分L】
Universe pleased with worker's work
Worker grade = 7
Main: worker completed work
*/
】 

紧耦合
现在,在南边一块古怪的土地上,有个工友名称叫Peter,他特别努力,对她的经理连连百顺百依。然而她的业主是个吝啬的人,从不相信赖别人,坚决必要任何时候精晓Peter的专门的学问进度,以堤防她偷懒。但是Peter又不想让业主呆在他的办公里站在背后瞧着她,于是就对业主做出承诺:不论哪天,只要自个儿的职业取得了少数张开小编都会立时让您驾驭。Peter通过周期性地使用“带项指标引用”(原版的书文为:“typed reference” 也正是delegate??卡塔尔(قطر‎“回调”他的小业主来贯彻他的承诺,如下:
class Worker {
    public void Advise(Boss boss) { _boss = boss; }
    public void DoWork() {
        Console.WriteLine(“职业: 专业始于”卡塔尔国;
        if( _boss != null ) _boss.WorkStarted();

        Console.WriteLine(“职业: 职业开展中”卡塔尔(قطر‎;
        if( _boss != null ) _boss.WorkProgressing();

        Console.WriteLine("“专业: 工作做到”"卡塔尔(قطر‎;
        if( _boss != null ) {
            int grade = _boss.WorkCompleted();
            Console.WriteLine(“工人的行事得分=” + grade卡塔尔;
    }
}
private Boss _boss;
}

class Boss {
    public void WorkStarted() { /* 首席实践官不爱惜。 */ }
    public void WorkProgressing() { /*业主不尊敬。 */ }
    public int WorkCompleted() {
        Console.WriteLine(“时间基本上!”卡塔尔;
        return 2; /* 总分为10 */
    }
}

class Universe {
    static void Main() {
        Worker peter = new Worker();
        Boss boss = new Boss();
        peter.Advise(boss);
        peter.DoWork();

        Console.WriteLine(“Main: 工人工作成功”卡塔尔(قطر‎;
        Console.ReadLine();
    }
}

接口

方今,彼得成了二个不拘一格的人,他不仅可以忍受吝啬的业主,并且和他方圆的大自然也会有了缜密的关系,以致于他认为宇宙对他的工作进程也感兴趣。不幸的是,他必得也给宇宙增多一个分裂平时的回调函数Advise来兑现同一时间向他高管和宇宙报告工作进程。彼得想要把地下的布告的列表和这么些公告的贯彻方式分别开来,于是她调控把措施分别为三个接口:

interface IWorkerEvents {
    void WorkStarted();
    void WorkProgressing();
    int WorkCompleted();
}

class Worker {
    public void Advise(IWorkerEvents events) { _events = events; }
    public void DoWork() {
        Console.WriteLine(“专门的学业: 职业启幕”卡塔尔(قطر‎;
        if( _events != null ) _events.WorkStarted();

        Console.WriteLine(“专门的工作: 工作张开中”State of Qatar;
        if(_events != null ) _events.WorkProgressing();

        Console.WriteLine("“专门的学问: 专门的学业产生”"卡塔尔(قطر‎;
        if(_events != null ) {
            int grade = _events.WorkCompleted();

            Console.WriteLine(“工人的做事得分=” + grade卡塔尔国;
            }
    }
    private IWorkerEvents _events;
}

class Boss : IWorkerEvents {
    public void WorkStarted() { /* 老板不关切。 */ }
    public void WorkProgressing() { /* COO不关切。 */ }
    public int WorkCompleted() {
        Console.WriteLine(“时间多数!”State of Qatar;
        return 3; /* 总分为10 */
    }
}

委托

不幸的是,每当Peter忙于通过接口的完毕和老董交换时,就从未机缘顿时文告宇宙了。最少她应该忽略身在塞外的CEO娘的引用,好让别的完结了IWorker伊夫nts的对象获得她的做事报告。(”At least he'd abstracted the reference of his boss far away from him so that others who implemented the IWorker伊夫nts interface could be notified of his work progress” 原话如此,不知晓到底是什么样意思 )

他的业主依然抱怨得相当棒。“Peter!”他COO吼道,“你干吗在办事一最初和行事张开中都来烦作者?!笔者不关切那一个事件。你非但免强作者达成了那个情势,何况还在浪费自个儿宝贵的办事时间来管理你的风浪,非常是当本身出门的时候更是如此!你能还是一定要再来烦小编?”

于是乎,Peter意识到接口即使在众多状态都很有用,不过当用作事件时,“粒度”相当不足好。他盼望能够仅在他人想要时才通告他们,于是他决定把接口的章程分别为独立的委托,各类委托都像二个小的接口方法:

delegate void WorkStarted();
delegate void WorkProgressing();
delegate int WorkCompleted();

class Worker {
    public void DoWork() {
        Console.WriteLine(“职业: 工作启幕”卡塔尔(قطر‎;
        if( started != null ) started();

        Console.WriteLine(“职业: 专业开展中”State of Qatar;
        if( progressing != null ) progressing();

        Console.WriteLine("“专业: 职业到位”"卡塔尔;
        if( completed != null ) {
            int grade = completed();
            Console.WriteLine(“工人的专门的工作得分=” + grade卡塔尔;
        }
    }
    public WorkStarted started;
    public WorkProgressing progressing;
    public WorkCompleted completed;
}

class Boss {
    public int WorkCompleted() {
    Console.WriteLine("Better...");
    return 4; /* 总分为10 */
}
}

class Universe {
    static void Main() {
        Worker peter = new Worker();
        Boss boss = new Boss();
        peter.completed = new WorkCompleted(boss.WorkCompleted);
        peter.DoWork();

        Console.WriteLine(“Main: 工人事业产生”卡塔尔(قطر‎;
        Console.ReadLine();
    }
}

静态监听者

诸有此类,Peter不会再拿他董事长不想要的平地风波来烦他组长了,然则她还尚无把宇宙放到他的监听者列表中。因为宇宙是个包容一切的实体,看来不契合接受实例方法的嘱托(想像一下,实例化二个“宇宙”要开销多少财富…..),于是Peter就供给可以对静态委托开展联络,委托对这点支撑得很好:

class Universe {
    static void WorkerStartedWork() {
        Console.WriteLine("Universe notices worker starting work");
    }

    static int WorkerCompletedWork() {
        Console.WriteLine("Universe 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: 工人专门的学问做到”卡塔尔;
        Console.ReadLine();
    }
}

事件

不幸的是,宇宙太忙了,也不习贯时刻关切它在那之中的私有,它能够用本身的嘱托替换了Peter老总的嘱托。那是把Peter的Worker类的的信托字段做成public的三个无意的副效能。同样,假诺Peter的COO娘不意志力了,也得以调整本身来激情Peter的嘱托(真是多少个强行的业主):

// Peter's boss taking matters into his own hands
if( peter.completed != null ) peter.completed();
Peter不想让这一个事爆发,他发掘到须求给每一种委托提供“注册”和“反注册”效率,那样监听者就能够团结丰盛和移除委托,但同时又不能够清空整个列表也不可能随随意便激发Peter的风浪了。Peter并不曾来源己实现那一个意义,相反,他采用了event关键字让C#编写翻译器为他创设这么些办法:

class Worker {
...
    public event WorkStarted started;
    public event WorkProgressing progressing;
    public event WorkCompleted completed;
}

彼获知道event关键字在信托的外地包装了贰个property,仅让C#顾客通过+= 和 -=操作符来增多和移除,强迫她的董事长娘和大自然精确地使用事件。

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: 工人专业做到”卡塔尔国;
    Console.ReadLine();
}

“收获”全部结果

到那时候,Peter终于得以送一口气了,他幸不辱命地满意了独具监听者的必要,同期防止了与一定达成的紧耦合。可是她小心到她的小业主和宇宙都为它的干活打了分,可是他一味接纳了一个分数。面临四个监听者,他想要“收获”全数的结果,于是他深刻到代办里面,轮询监听者列表,手工业一个个调用:

public void DoWork() {
    ...
    Console.WriteLine("“职业: 事业成功”"State of Qatar;
    if( completed != null ) {
        foreach( WorkCompleted wc in completed.GetInvocationList() ) {
            int grade = wc();
            Console.WriteLine(“工人的劳作得分=” + gradeState of Qatar;
        }
    }
}

异步通知:激发 & 忘掉

何况,他的主任和宇宙还要忙于管理任何作业,也正是说他们给Peter打分所开销的事件变得要命长:

class Boss {
    public int WorkCompleted() {
        System.Threading.Thread.Sleep(3000);
        Console.WriteLine("Better..."); return 6; /* 总分为10 */
    }
}

class Universe {
    static int WorkerCompletedWork() {
        System.Threading.Thread.Sleep(4000);
        Console.WriteLine("Universe is pleased with worker's work");
        return 7;
    }
    ...
}
特不幸,Peter每一趟文告二个监听者后必须等待它给本身打分,今后这几个布告花费了她太多的做事事件。于是他调节忘掉分数,仅仅异步激发事件:

public void DoWork() {
    ...
    Console.WriteLine("“专门的学问: 职业做到”"State of Qatar;
    if( completed != null ) {
        foreach( WorkCompleted wc in completed.GetInvocationList() )
        {
            wc.BeginInvoke(null, null);
        }
    }
}

异步公告:轮询

那使得Peter能够公告她的监听者,然后立时回去专门的学问,让进度的线程池来调用那几个代理。随着年华的过去,Peter发现他不见了他干活的举报,他精通听取外人的夸赞和奋力干活肖似主要,于是她异步激发事件,但是周期性地轮询,得到可用的分数。

public void DoWork() {
    ...
    Console.WriteLine("“专门的学业: 工作做到”"卡塔尔(قطر‎;
    if( completed != null ) {
        foreach( WorkCompleted wc in completed.GetInvocationList() ) {
            IAsyncResult res = wc.BeginInvoke(null, null);
            while( !res.IsCompleted ) System.Threading.Thread.Sleep(1);
            int grade = wc.EndInvoke(res);
            Console.WriteLine(“工人的行事得分=” + grade卡塔尔;
        }
    }
}

异步布告:委托

噩运地,Peter有再次回到了一发端就想幸免的情况中来,举个例子,COO站在泰然自若瞧着他干活。于是,他操纵接受自身的委托作为他调用的异步委托达成的公告,让他自个儿立刻赶回专业,可是还可以够在人家给他的办事打分后获取照看:

    public void DoWork() {
        ...
        Console.WriteLine("“专门的学问: 专门的学问成就”"卡塔尔;
        if( completed != null ) {
            foreach( WorkCompleted wc in completed.GetInvocationList() ) {
                wc.BeginInvoke(new AsyncCallback(WorkGraded), wc);
            }
        }
    }

    private void WorkGraded(IAsyncResult res) {
        WorkCompleted wc = (WorkCompleted)res.AsyncState;
        int grade = wc.EndInvoke(res);
        Console.WriteLine(“工人的干活得分=” + grade卡塔尔国;
    }

大自然中的幸福

Peter、他的小业主和宇宙最终都知足了。Peter的董事长娘和大自然能够接过他们感兴趣的平地风波通报,收缩了实现的担任和非必须的往返“差旅费”。Peter能够文告他们,而无论是他们要花多久来从指标方法中回到,同期又能够异步地得到她的结果。Peter悉道,那并不*十分*轻便易行,因为当他异步激发事件时,方法要在此外二个线程中实践,Peter的目标方法成功的打招呼也是大同小异的道理。然则,Mike和Peter是好相恋的人,他很熟习线程的事情,能够在此个领域提供指引。

她俩永远幸福地生存下去……<完>

本文由10bet手机官网发布于web前端,转载请注明出处:委托和事件,睡前故事

上一篇:提示的种种原因及解决方法小结,DEDE栏目生成错误 下一篇:没有了
猜你喜欢
热门排行
精彩图文