The PROPID_M_CORRELATIONID property specifies the correlation identifier of the message.
When sending a message, PROPID_M_CORRELATIONID provides an application-defined identifier that the receiving application can use to sort the message.
When sending response messages to the sending application, PROPID_M_CORRELATIONID can be set to the message identifier (PROPID_M_MSGID) of the message that is in the queue. This provides an easy mechanism that the sending application can use to match the response message with the message that was sent.
When MSMQ generates an acknowledgment message, it uses the PROPID_M_CORRELATIONID property to specify the message identifier of the original message. The application can then look at the PROPID_M_CORRELATIONID property to find the message identifier of the original message.
For information on negative and positive acknowledgment messages in administration queues, see Administration Queues.
When sending messages to a foreign queue, the value of PROPID_M_CORRELATIONID is used to verify the sender's signature.