MessagePropertyFilter.Acknowledgment Property

 
System_CAPS_noteNote

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Gets or sets a value that indicates whether to retrieve Message.Acknowledgment property information when receiving or peeking a message.

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

[MessagingDescriptionAttribute("MsgAcknowledgement")]
public bool Acknowledgment { get; set; }

Property Value

Type: System.Boolean

true to receive Message.Acknowledgment information; otherwise, false. The default is true.

The Message.Acknowledgment property of the Message class specifies the type of acknowledgment messages the system posts in the administration queue, which determines when acknowledgments are generated.

Acknowledgments are returned from the destination queue and posted as messages to the AdministrationQueue specified by the original message. The type of acknowledgment generated depends on what was requested.

Read the Message.Acknowledgment property when receiving a message from an administration queue to verify the status of the message originally sent to the message queue.

The following code example sends and receives a message that contains an order to and from a queue. It specifically requests a positive acknowledgment when the original message reaches or is retrieved from the queue.

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 sends and receives a message from
		// a queue.
		//**************************************************

		public static void Main()
		{
			// Create a new instance of the class.
			MyNewQueue myNewQueue = new MyNewQueue();

			// Create new queues.
			CreateQueue(".\\myQueue");
			CreateQueue(".\\myAdministrationQueue");

			// Send messages to a queue.
			myNewQueue.SendMessage();

			// Receive messages from a queue.
			string messageId = myNewQueue.ReceiveMessage(); 

			// Receive acknowledgment message.
			if(messageId != null)
			{
				myNewQueue.ReceiveAcknowledgment(messageId, ".\\myAdministrationQueue");
			}

			return;
		}

		//**************************************************
		// Creates a new queue.
		//**************************************************

		public static void CreateQueue(string queuePath)
		{
			try	
			{
				if(!MessageQueue.Exists(queuePath))
				{
					MessageQueue.Create(queuePath);
				}
				else
				{
					Console.WriteLine(queuePath + " already exists.");
				}
			}
			catch (MessageQueueException e)
			{
				Console.WriteLine(e.Message);
			}

		}


		//**************************************************
		// Sends a string message to a queue.
		//**************************************************

		public void SendMessage()
		{

			// Connect to a queue on the local computer.
			MessageQueue myQueue = new MessageQueue(".\\myQueue");

			// Create a new message.
			Message myMessage = new Message("Original Message"); 

			myMessage.AdministrationQueue = new MessageQueue(".\\myAdministrationQueue");
			myMessage.AcknowledgeType = AcknowledgeTypes.PositiveReceive | AcknowledgeTypes.PositiveArrival;

			// Send the Order to the queue.
			myQueue.Send(myMessage);

			return;
		}


		//**************************************************
		// Receives a message containing an Order.
		//**************************************************

		public  string ReceiveMessage()
		{
			// Connect to the a queue on the local computer.
			MessageQueue myQueue = new MessageQueue(".\\myQueue");

			myQueue.MessageReadPropertyFilter.CorrelationId = true;


			// Set the formatter to indicate body contains an Order.
			myQueue.Formatter = new XmlMessageFormatter(new Type[]
				{typeof(string)});

			string returnString = null;

			try
			{
				// Receive and format the message. 
				Message myMessage =	myQueue.Receive(); 


				// Display message information.
				Console.WriteLine("____________________________________________");
				Console.WriteLine("Original message information--");
				Console.WriteLine("Body: " +myMessage.Body.ToString());
				Console.WriteLine("Id: " + myMessage.Id.ToString());
				Console.WriteLine("____________________________________________");

				returnString =  myMessage.Id;

			}

			catch (MessageQueueException)
			{
				// Handle Message Queuing exceptions.
			}

			// Handle invalid serialization format.
			catch (InvalidOperationException e)
			{
				Console.WriteLine(e.Message);
			}

			// Catch other exceptions as necessary.

			return returnString;
		}

		//**************************************************
		// Receives a message containing an Order.
		//**************************************************

		public void ReceiveAcknowledgment(string messageId, string queuePath)
		{
			bool found = false;
			MessageQueue queue = new MessageQueue(queuePath);
			queue.MessageReadPropertyFilter.CorrelationId = true;
			queue.MessageReadPropertyFilter.Acknowledgment = true;

			try
			{
				while(queue.PeekByCorrelationId(messageId) != null)
				{
					Message myAcknowledgmentMessage = queue.ReceiveByCorrelationId(messageId);

					// Output acknowledgment message information. The correlation Id is identical
					// to the id of the original message.
					Console.WriteLine("Acknowledgment Message Information--");
					Console.WriteLine("Correlation Id: " + myAcknowledgmentMessage.CorrelationId.ToString());
					Console.WriteLine("Id: " + myAcknowledgmentMessage.Id.ToString());
					Console.WriteLine("Acknowledgment Type: " + myAcknowledgmentMessage.Acknowledgment.ToString());
					Console.WriteLine("____________________________________________");

					found = true;
				}
			}
			catch (InvalidOperationException e)
			{ 
				// This exception would be thrown if there is no (further) acknowledgment message
				// with the specified correlation Id. Only output a message if there are no messages;
				// not if the loop has found at least one.
				if(found == false)
				{	
					Console.WriteLine(e.Message);
				}

				// Handle other causes of invalid operation exception.
			}

		}
	}
}

.NET Framework
Available since 1.1
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