Applies To: Windows 10, Windows 7, Windows 8, Windows 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server Technical Preview, Windows Vista

(Introduced in MSMQ 3.0.) The LookupId property of the MSMQMessage object provides the lookup identifier of the message.

Data type: Variant (String)
Run-time access: Read-only
Property LookupId As Variant  

Property Value

A Variant containing a string representation of the 64-bit lookup identifier of the message.


The lookup identifier of a message is a 64-bit, local number (in C++, a VARIANT containing a ULONGLONG) that is set by the target queue manager when the queue manager places the message in the queue. The lookup identifier of a message is unique with respect to the queue, and is always greater than the lookup identifier of the preceding message and less then the lookup identifier of the following message.

All messages placed in a queue have a lookup identifier. This includes messages sent by applications and messages sent by Message Queuing.

The receiving application can use the lookup identifier when calling one of the following methods.

For information on navigating queues using lookup identifiers, see Navigating with Lookup Identifiers.

Message Queuing COM components ignore any characters that follow the first Null character in a string without returning an error.

In C++ COM applications, you must use a smart pointer to the IMSMQMessage3 interface to expose the LookupId property.

Equivalent API Function Property

With API function calls, the equivalent property is PROPID_M_LOOKUPID.


Windows NT/2000/XP: Included in Windows XP and Windows Server 2003.

Windows 95/98/Me: Unsupported.

Header: Declared in Mqoai.h.

Library: Use Mqoa.lib.

See Also