Export (0) Print
Expand All

PeekCompletedEventArgs Class

Provides data for the PeekCompleted event. When your asynchronous peek operation calls an event handler, an instance of this class is passed to the handler.

Namespace:  System.Messaging
Assembly:  System.Messaging (in System.Messaging.dll)

public class PeekCompletedEventArgs : EventArgs

When you use event notification to peek (read without removing) messages asynchronously from the queue, you must create a method that handles your message processing. Your code must call BeginPeek to begin the asynchronous processing. When a message is peeked, your application is notified through the PeekCompleted event. An instance of PeekCompletedEventArgs is passed into the event delegate that calls your event handler. The data associated with the PeekCompleted event is contained in the delegate's AsyncResult parameter.

There are two ways to provide notification of event completion: event notification and callbacks. PeekCompletedEventArgs is used only with event notification. For information comparing callbacks and event notification, see "Events vs. Callbacks" on MSDN.

PeekCompletedEventArgs provides access to the message that initiated the end of the asynchronous peek operation, through the Message member. This is an alternate access to the message, and behaves much the same as a call to MessageQueue.EndPeek.

The following code example creates an event handler for the PeekCompleted event and associates it with the event delegate by using the PeekCompletedEventHandler. The event handler, MyPeekCompleted, peeks a message and writes its label to the screen.

using System;
using System.Messaging;

namespace MyProject
{
	/// <summary> 
	/// Provides a container class for the example. 
	/// </summary> 
	public class MyNewQueue
	{

		//************************************************** 
		// Provides an entry point into the application. 
		//		  
		// This example performs asynchronous peek operation 
		// processing. 
		//************************************************** 

		public static void Main()
		{
			// Create an instance of MessageQueue. Set its formatter.
			MessageQueue myQueue = new MessageQueue(".\\myQueue");
			myQueue.Formatter = new XmlMessageFormatter(new Type[]
				{typeof(String)});

			// Add an event handler for the PeekCompleted event.
			myQueue.PeekCompleted += new 
				PeekCompletedEventHandler(MyPeekCompleted);
			
			// Begin the asynchronous peek operation.
			myQueue.BeginPeek();
			
			// Do other work on the current thread. 

			return;
		}


		//************************************************** 
		// Provides an event handler for the PeekCompleted 
		// event. 
		//************************************************** 
		
		private static void MyPeekCompleted(Object source, 
			PeekCompletedEventArgs asyncResult)
		{
			// Connect to the queue.
			MessageQueue mq = (MessageQueue)source;

			// End the asynchronous peek operation.
			Message m = mq.EndPeek(asyncResult.AsyncResult);

			// Display message information on the screen.
			Console.WriteLine("Message: " + (string)m.Body);

			// Restart the asynchronous peek operation.
			mq.BeginPeek();
			
			return; 
		}
	}
}
#using <mscorlib.dll>
#using <system.dll>
#using <system.messaging.dll>

using namespace System;
using namespace System::Messaging;

// This example performs asynchronous peek operation
// processing.
//*************************************************

__gc class MyNewQueue 
{
// Provides an event handler for the PeekCompleted
// event.
public:
	static void MyPeekCompleted(Object* source, PeekCompletedEventArgs* asyncResult) 
	{
		// Connect to the queue.
		MessageQueue* mq = dynamic_cast<MessageQueue*>(source);

		// End the asynchronous peek operation.
		Message* m = mq->EndPeek(asyncResult->AsyncResult);

		// Display message information on the screen.
		Console::WriteLine(S"Message: {0}", static_cast<String*>(m->Body));

		// Restart the asynchronous peek operation.
		mq->BeginPeek();

		return; 
	}
};

// Provides an entry point into the application.
//         

int main() 
{
	// Create an instance of MessageQueue. Set its formatter.
	MessageQueue* myQueue = new MessageQueue(S".\\myQueue");

	Type* p __gc[] = new Type* __gc[1];
	p[0] = __typeof(String);
	myQueue->Formatter = new XmlMessageFormatter( p );

	// Add an event handler for the PeekCompleted event.
	myQueue->PeekCompleted += new PeekCompletedEventHandler(0, MyNewQueue::MyPeekCompleted);

	// Begin the asynchronous peek operation.
	myQueue->BeginPeek();

	// Do other work on the current thread.

	return 0;
}

System.Object
  System.EventArgs
    System.Messaging.PeekCompletedEventArgs

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

Community Additions

ADD
Show:
© 2014 Microsoft