The MSMQEvent object can be used to implement a single event handler that can support multiple queues. These events include a message arriving at the queue, an error occurring while the message is being delivered to the queue, or (when asynchronously reading messages) no message arriving at the queue before its receive timeout timer expires.
Each MSMQ queue can be associated with an instance of the MSMQEvent object. This allows the applications to have one generic event handler that can treat all common tasks identically, and use the queue handle passed to the event handler for special-case situations.
Note The formal parameter passed to the MSMQEvent_Arrived event is of type Object (this is required because event firing is implemented in terms of IDispatch), which means that the event handler uses ActiveX late-binding by default instead of early-binding. However, early-binding is more efficient and the applications may choose to assign the formal parameter to a local variable of type MSMQQueue to regain the benefits of early-binding.
For an example of an event handler, see Reading Messages Asynchronously.