MessageQueue.ReceiveCompleted Event

Definition

Namespace:

System.Messaging

Assembly:

System.Messaging.dll

Occurs when a message has been removed from the queue. This event is raised by the asynchronous operation, BeginReceive().

C#

[System.Messaging.MessagingDescription("MQ_ReceiveCompleted")]
public event System.Messaging.ReceiveCompletedEventHandler ReceiveCompleted;

Event Type

ReceiveCompletedEventHandler

Attributes

MessagingDescriptionAttribute

Examples

The following code example creates an event handler named MyReceiveCompleted, attaches it to the ReceiveCompleted event handler delegate, and calls BeginReceive to initiate an asynchronous receive operation on the queue that is located at the path ".\myQueue". When a ReceiveCompleted event is raised, the example receives the message and writes its body to the screen. The example then calls BeginReceive again to initiate a new asynchronous receive operation.

C#

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 receive 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 ReceiveCompleted event.
            myQueue.ReceiveCompleted += new
                ReceiveCompletedEventHandler(MyReceiveCompleted);
            
            // Begin the asynchronous receive operation.
            myQueue.BeginReceive();
            
            // Do other work on the current thread.

            return;
        }

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

            // End the asynchronous Receive operation.
            Message m = mq.EndReceive(asyncResult.AsyncResult);

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

            // Restart the asynchronous Receive operation.
            mq.BeginReceive();
            
            return;
        }
    }
}

Remarks

BeginReceive is used in asynchronous processing to raise the ReceiveCompleted event when a message is available in the queue.

EndReceive(IAsyncResult) is used to complete the operation initiated by a call to BeginReceive and peek the message when the ReceiveCompleted event is raised.

When you create a ReceiveCompletedEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event handler delegates, see Handling and Raising Events.

Applies to

See also

• BeginReceive()
• PeekCompleted
• TimeSpan
• AsyncCallback
• IAsyncResult