Message::CorrelationId Property
Gets or sets the message identifier used by acknowledgment, report, and response messages to reference the original message.
Assembly: System.Messaging (in System.Messaging.dll)
public: [MessagingDescriptionAttribute("MsgCorrelationId")] property String^ CorrelationId { String^ get(); void set(String^ value); }
Property Value
Type: System::String^The message identifier specified by the Id property of the original message. The correlation identifier is used by Message Queuing when it generates an acknowledgment or report message, and by an application when it generates a response message.
| Exception | Condition |
|---|---|
| InvalidOperationException | The message queue is filtered to ignore the CorrelationId property. |
| ArgumentException | The CorrelationId is null. |
When Message Queuing generates an acknowledgment or report message, it uses the correlation identifier property to specify the message identifier of the original message. In this manner, the correlation identifier ties the report or acknowledgment message to the original message.
The sending application can then match the acknowledgment or report with the original message by using the CorrelationId property to identify the original message's Id property.
Connector applications also must set the CorrelationId property of the acknowledgment and report messages to the message identifier of the original message.
When your application sends a response message to the sending application, you can set the CorrelationId property of the response message to the message identifier of the original message. The sending application can then match your response message to the message that was sent.
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.dll> #using <system.messaging.dll> using namespace System; using namespace System::Messaging; ref class MyNewQueue { public: static void CreateQueue( String^ queuePath ) { try { if ( !MessageQueue::Exists( queuePath ) ) { MessageQueue::Create( queuePath ); } else { Console::WriteLine( "{0} already exists.", queuePath ); } } catch ( MessageQueueException^ e ) { Console::WriteLine( e->Message ); } } void SendMessage() { // Connect to a queue on the local computer. MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" ); // Create a new message. Message^ myMessage = gcnew Message( "Original Message" ); myMessage->AdministrationQueue = gcnew MessageQueue( ".\\myAdministrationQueue" ); myMessage->AcknowledgeType = (AcknowledgeTypes)(AcknowledgeTypes::PositiveReceive | AcknowledgeTypes::PositiveArrival); // Send the Order to the queue. myQueue->Send( myMessage ); return; } String^ ReceiveMessage() { // Connect to the a queue on the local computer. MessageQueue^ myQueue = gcnew MessageQueue( ".\\myQueue" ); myQueue->MessageReadPropertyFilter->CorrelationId = true; array<Type^>^p = gcnew array<Type^>(1); p[ 0 ] = String::typeid; myQueue->Formatter = gcnew XmlMessageFormatter( p ); String^ returnString = nullptr; try { // Receive and format the message. Message^ myMessage = myQueue->Receive(); // Display message information. Console::WriteLine( "____________________________________________" ); Console::WriteLine( "Original message information--" ); Console::WriteLine( "Body: {0}", myMessage->Body ); Console::WriteLine( "Id: {0}", myMessage->Id ); 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; } void ReceiveAcknowledgment( String^ messageId, String^ queuePath ) { bool found = false; MessageQueue^ queue = gcnew MessageQueue( queuePath ); queue->MessageReadPropertyFilter->CorrelationId = true; queue->MessageReadPropertyFilter->Acknowledgment = true; try { while ( queue->PeekByCorrelationId( messageId ) != nullptr ) { 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: {0}", myAcknowledgmentMessage->CorrelationId ); Console::WriteLine( "Id: {0}", myAcknowledgmentMessage->Id ); Console::WriteLine( "Acknowledgment Type: {0}", myAcknowledgmentMessage->Acknowledgment ); 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. } } }; int main() { // Create a new instance of the class. MyNewQueue^ myNewQueue = gcnew MyNewQueue; // Create new queues. MyNewQueue::CreateQueue( ".\\myQueue" ); MyNewQueue::CreateQueue( ".\\myAdministrationQueue" ); // Send messages to a queue. myNewQueue->SendMessage(); // Receive messages from a queue. String^ messageId = myNewQueue->ReceiveMessage(); // Receive acknowledgment message. if ( messageId != nullptr ) { myNewQueue->ReceiveAcknowledgment( messageId, ".\\myAdministrationQueue" ); } return 0; }
Available since 1.1