ÇÔ¸Õ¡ÒÃàÃÕ¡àÁ¸Í´ Visual c# asynchronously

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• Microsoft Windows 2000 ËÃ×Í Microsoft Windows XP ËÃ×Í Microsoft Windows Server 2003
• visual Studio .NET ËÃ×Í Visual Studio 2005

• ÇÔ¸Õ¡ÒÃâ·ÃÈѾ·ìã¹ Visual c#
• ÇÔ¸Õ¡ÒÃãªé¼ÙéÃѺÁͺÊÔ·¸Ôì

ÇÔ¸Õ¡Ò÷Õè·ÓãËé¾×é¹·ÕèẺÍЫԧâ¤Ã¹ÑÊ

// The following delegate 
delegate string MethodDelegate(int iCallTime, out int iExecThread)  ;

// will have the following BeginInvoke() and EndInvoke methods:
IAsyncResult MethodDelegate.BeginInvoke(int iCallTime, out int iExecThread, AsyncCallback cb, object AsyncState); 

string MethodDelegate.EndInvoke (out int iExecThread, IAsyncResult ar) ;
				

• ÍÕ¡ÇÔ¸Õ˹Ö觤×ÍäÁè·Ó§Ò¹Í×è¹ æ áÅÐãªéEndInvoke().
• ¢ÍÃѺµÑÇWaitHandle·ÕèãËéäÇéâ´ÂIAsyncResultÇѵ¶Ø ãªé¹Ñé¹WaitOneÇÔ¸Õ¡ÒúÅçÍ¡¨¹¶Ö§¡ÒÃWaitHandleÁÕ signaled áÅÐàÃÕ¡ãªéáÅéÇEndInvoke().
• â¾ÅIAsyncResultÇѵ¶Ø¡ÒõÃǨÊͺàÁ×èÍ¡ÒÃàÃÕ¡ẺÍЫԧâ¤Ã¹ÑÊàÊÃç¨ÊÁºÙóìáÅéÇ áÅСÒÃàÃÕ¡áÅéÇEndInvoke().
• Ãкº¨ÐàÃÕ¡ãªé¿Ñ§¡ìªÑ¹àÃÕ¡¡ÅѺ·Õè¤Ø³ÃкØä´é àÃÕ¡¿Ñ§¡ìªÑ¹¹ÕéàÃÕ¡¡ÅѺEndInvoke()áÅСÃкǹ¡ÒüÅÅѾ¸ì¢Í§¡ÒÃàÃÕ¡ẺÍЫԧâ¤Ã¹ÑÊàÁ×èͤسàÊÃç¨ÊÁºÙóì

string LongRunningMethod (int iCallTime, out int iExecThread)
{
	Thread.Sleep (iCallTime) ;
	iExecThread = AppDomain.GetCurrentThreadId ();
	return "MyCallTime was " + iCallTime.ToString() ;
}

				

delegate string MethodDelegate(int iCallTime, out int iExecThread)  ;
				

µÑÇÍÂèÒ§·Õè 1: àÃÕ¡ÇÔ¸Õ¡Òà Synchronously

1. àÃÔèÁ Microsoft Visual Studio .NET ËÃ×Í Microsoft Visual Studio 2005
2. ÊÃéÒ§â¤Ã§¡Òà Visual c# ¤Í¹â«Åá;¾ÅÔपѹãËÁèª×èÍ AsyncDemo
3. à¾ÔèÁ¤ÅÒÊ·ÕèÃÐºØ AsyncDemo ·Õè¡Ó˹´äÇéà»ç¹´Ñ§¹Õé¡Ñºâ¤Ã§¡ÒÃã¹á¿éÁ.cs ãËÁè:

   using System;
   using System.Threading ; 
   using System.Windows.Forms ;
   
   public class AsyncDemo
   {
   	string LongRunningMethod (int iCallTime, out int iExecThread)
   	{
   		Thread.Sleep (iCallTime) ;
   		iExecThread = AppDomain.GetCurrentThreadId ();
   		return "MyCallTime was " + iCallTime.ToString() ;
   	}
   
   	delegate string MethodDelegate(int iCallTime, out int iExecThread)  ;
   
   	public void DemoSyncCall()
   	{
   		string s ;
   		int iExecThread;
   
   		// Create an instance of a delegate that wraps LongRunningMethod.
   		MethodDelegate dlgt = new MethodDelegate (this.LongRunningMethod) ;  
   			
   		// Call LongRunningMethod using the delegate.
   		s = dlgt(3000, out iExecThread);  
   			
   		MessageBox.Show (string.Format ("The delegate call returned the string:   \"{0}\", 
                                           and the thread ID {1}", s, iExecThread.ToString() ) );
   	}
   }
   					

   ã¹ÀÒÂËÅѧ ¤ÅÒ¹Õé͸ԺÒÂÇÔ¸Õ¡Ò÷Õè·Ó¡ÒÃàÃÕ¡ẺÍЫԧâ¤Ã¹ÑÊ àÃÔèÁµé¹´éÇ ÍÂèÒ§äáçµÒÁ à·èÒ¹Ñé¹»ÃСͺ´éÇ¡ÒÃDemoSyncCall()ÇÔ¸Õ «Öè§Í¸ÔºÒÂÇÔ¸Õ¡ÒÃàÃÕ¡¼ÙéÃѺÁͺÊÔ·¸Ôì synchronously
4. à¾ÔèÁÃËÑʵèÍ仹Õéã¹à¹×éͤÇÒÁ¢Í§ËÅÑ¡¿Ñ§¡ìªÑ¹·Õè Visual Studio ·ÕèÊÃéÒ§â´ÂÍѵâ¹ÁѵÔã¹â¤Ã§¡Òâͧ¤Ø³:

   static void Main(string[] args)
   {
   	AsyncDemo ad = new AsyncDemo () ;
   	ad.DemoSyncCall() ;
   }
   					

5. ¡´ CTRL + F5 à¾×èÍàÃÕ¡ãªéâ»Ãá¡ÃÁ»ÃÐÂØ¡µì¢Í§¤Ø³

µÑÇÍÂèÒ§·Õè 2: àÃÕ¡ÇÔ¸Õ A Asynchronously â´Âãªé¡ÒÃEndInvoke()àÃÕ¡ãªéÅÇ´ÅÒÂ

1. à¾ÔèÁÇÔ¸Õ¡ÒõÑ駪×èÍDemoEndInvoke()ä»AsyncDemo¤ÅÒÊ·Õè ¡Ãкǹ¡ÒÃDemoEndInvoke¿Ñ§¡ìªÑ¹Í¸ÔºÒÂÇÔ¸Õ¡ÒÃàÃÕ¡¼ÙéÃѺÁͺÊÔ·¸Ôì asynchronously

   public void DemoEndInvoke()
   {
   	MethodDelegate dlgt = new MethodDelegate (this.LongRunningMethod) ;
   	string s ;
   	int iExecThread;
   
   	// Initiate the asynchronous call.
   	IAsyncResult ar = dlgt.BeginInvoke(3000, out iExecThread, null, null);  
   
   	// Do some useful work here. This would be work you want to have
   	// run at the same time as the asynchronous call.
   
   	// Retrieve the results of the asynchronous call.
   	s = dlgt.EndInvoke (out iExecThread, ar) ;  
   
   	MessageBox.Show (string.Format ("The delegate call returned the string:   \"{0}\", 
                                  and the number {1}", s, iExecThread.ToString() ) );
   }
   					

2. ÃËÑÊáËÅ觷ÕèÁÒÊÓËÃѺá¡éä¢ËÅÑ¡à¾×èÍ·Õè¨Ð»ÃСͺ´éÇÂÃËÑʵèÍ仹Õé:

   static void Main(string[] args)
   {
   	AsyncDemo ad = new AsyncDemo () ;
   	ad.DemoEndInvoke() ;
   }
   					

3. ¡´ CTRL + F5 à¾×èÍàÃÕ¡ãªéâ»Ãá¡ÃÁ»ÃÐÂØ¡µì¢Í§¤Ø³

µÑÇÍÂèÒ§·Õè 3: ¡ÒÃàÃÕ¡ÇÔ¸Õ A Asynchronously áÅСÒÃãªé¡Òà WaitHandle ¡ÒÃÃÍÊÓËÃѺ¡ÒÃàÃÕ¡价ÕèÊÁºÙóì

1. à¾ÔèÁª×èͿѧ¡ìªÑ¹DemoWaitHandle()ä»AsyncDemo¤ÅÒÊ·Õè ¡Ãкǹ¡ÒÃDemoWaitHandle()¿Ñ§¡ìªÑ¹Í¸ÔºÒÂÇÔ¸Õ¡ÒÃàÃÕ¡¼ÙéÃѺÁͺÊÔ·¸Ôì asynchronously

   public void DemoWaitHandle ()
   {
   	string s ;
   	int iExecThread;
   
   	MethodDelegate dlgt = new MethodDelegate (this.LongRunningMethod) ;
   
   	// Initiate the asynchronous call.
   	IAsyncResult ar = dlgt.BeginInvoke(3000, out iExecThread, null, null); 
   
   	// Do some useful work here. This would be work you want to have
   	// run at the same time as the asynchronous call.
   
   	// Wait for the WaitHandle to become signaled.
   	ar.AsyncWaitHandle.WaitOne() ;
   
   	// Get the results of the asynchronous call.
   	s = dlgt.EndInvoke (out iExecThread, ar) ;
   			
   	MessageBox.Show (string.Format ("The delegate call returned the string:   \"{0}\", 
                                    and the number {1}", s, iExecThread.ToString() ) );
   }
   					

2. ÃËÑÊáËÅ觷ÕèÁÒÊÓËÃѺá¡éä¢ËÅÑ¡à¾×èÍ·Õè¨Ð»ÃСͺ´éÇÂÃËÑʵèÍ仹Õé:

   static void Main(string[] args)
   {
   	AsyncDemo ad = new AsyncDemo () ;
   	ad.DemoWaitHandle () ;
   }
   					

3. ¡´ CTRL + F5 à¾×èÍàÃÕ¡ãªéâ»Ãá¡ÃÁ»ÃÐÂØ¡µì¢Í§¤Ø³

µÑÇÍÂèÒ§·Õè 4: àÃÕ¡ÇÔ¸Õ A Asynchronously â´ÂãªéÃٻẺ¡ÒõԴµèÍ Polling

1. à¾ÔèÁª×èͿѧ¡ìªÑ¹DemoPolling()ä»AsyncDemo¤ÅÒÊ·Õè ¡Ãкǹ¡ÒÃDemoPolling()¿Ñ§¡ìªÑ¹Í¸ÔºÒÂÇÔ¸Õ¡ÒÃàÃÕ¡¼ÙéÃѺÁͺÊÔ·¸Ôì asynchronously áÅÐãªé polling à¾×èÍ´ÙÇèÒ¡Ãкǹ¡ÒÃàÊÃç¨ÊÁºÙóì

   public void DemoPolling()
   {
   	MethodDelegate dlgt = new MethodDelegate (this.LongRunningMethod) ;
   	string s ;
   	int iExecThread;
   
   	// Initiate the asynchronous call.
   	IAsyncResult ar = dlgt.BeginInvoke(3000, out iExecThread, null, null); 
   
   	// Poll IAsyncResult.IsCompleted
   	while(ar.IsCompleted == false)
   	{
   		Thread.Sleep (10) ;  // pretend to so some useful work
   	}
   	s = dlgt.EndInvoke (out iExecThread, ar) ;
   
   	MessageBox.Show (string.Format ("The delegate call returned the string:   \"{0}\", 
                                   and the number {1}", s, iExecThread.ToString() ) );
   }
   
   					

2. ÃËÑÊáËÅ觷ÕèÁÒÊÓËÃѺá¡éä¢ËÅÑ¡. á·¹à¹×éÍËҢͧ¿Ñ§¡ìªÑ¹·Õè ÁÕÃËÑʵèÍ仹Õé:

   static void Main(string[] args)
   {
   	AsyncDemo ad = new AsyncDemo () ;
   	ad.DemoPolling () ;
   }
   					

3. ¡´ CTRL + F5 à¾×èÍàÃÕ¡ãªéâ»Ãá¡ÃÁ»ÃÐÂØ¡µì¢Í§¤Ø³

µÑÇÍÂèÒ§·Õè 5: ¡ÓÅѧãªé¡ÒÃàÃÕ¡¡ÅѺàÁ×èÍÇÔ¸Õ¡ÒÃẺÍЫԧâ¤Ã¹ÑÊàÊÃç¨ÊÁºÙóì

1. à¾ÔèÁ¡ÒÃÊͧÇÔ¸Õ¡ÒõÑ駪×èÍDemoCallback()áÅÐMyAsyncCallback()ä»AsyncDemo¤ÅÒÊ·Õè ¡Ãкǹ¡ÒÃDemoCallback()ÇÔ¸ÕáÊ´§ÇÔ¸Õ¡ÒÃàÃÕ¡¼ÙéÃѺÁͺÊÔ·¸Ôì asynchronously â»Ãá¡ÃÁ¨Ðãªéà»ç¹¼ÙéÃѺÁͺÊÔ·¸Ôìà¾×èÍ·ÕèµÑ´¡ÒÃMyAsyncCallback()ÇÔ¸Õ «Öè§ÃкºàÃÕ¡àÁ×èÍ¡ÒôÓà¹Ô¹¡ÒÃẺÍЫԧâ¤Ã¹ÑÊàÊÃç¨ÊÁºÙóìMyAsyncCallback()¡ÒÃàÃÕ¡EndInvoke().

   public void DemoCallback()
   {
   	MethodDelegate dlgt = new MethodDelegate (this.LongRunningMethod) ;
   	string s ;
   	int iExecThread;
   
   	// Create the callback delegate.
   	AsyncCallback cb = new AsyncCallback(MyAsyncCallback);
   
   	// Initiate the Asynchronous call passing in the callback delegate
   	// and the delegate object used to initiate the call.
   	IAsyncResult ar = dlgt.BeginInvoke(3000, out iExecThread, cb, dlgt); 
   }
   
   public void MyAsyncCallback(IAsyncResult ar)
   {
   	string s ;
   	int iExecThread ;
   
   	// Because you passed your original delegate in the asyncState parameter
   	// of the Begin call, you can get it back here to complete the call.
   	MethodDelegate dlgt = (MethodDelegate) ar.AsyncState;
   
   	// Complete the call.
   	s = dlgt.EndInvoke (out iExecThread, ar) ;
   
   	MessageBox.Show (string.Format ("The delegate call returned the string:   \"{0}\", 
                                   and the number {1}", s, iExecThread.ToString() ) );
   }
   
   					

2. ÃËÑÊáËÅ觷ÕèÁÒÊÓËÃѺá¡éä¢ËÅÑ¡. á·¹à¹×éÍËҢͧ¿Ñ§¡ìªÑ¹·Õè ÁÕÃËÑʵèÍ仹Õé:

   static void Main(string[] args)
   {
   	AsyncDemo ad = new AsyncDemo () ;
   	ad.DemoCallback() ;
   }
   					

3. ¡´ CTRL + F5 à¾×èÍàÃÕ¡ãªéâ»Ãá¡ÃÁ»ÃÐÂØ¡µì¢Í§¤Ø³

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