Developing Queued Components

The COM+ queued components service requires all application methods to contain only [in] parameters, with no return values. Because the server object is not necessarily available when the client makes the call, server results can be returned by sending a message that creates another object. In this way, two-way communication occurs not in every case but only when it is required, by a series of one-way messages between objects.

To use the COM+ queued components service, you must have the Message Queuing service already installed. Message Queuing is not installed automatically. Message Queuing must be selected during the operating system setup or by using Add/Remove programs. An internal Message Queuing certificate is created automatically at logon.

The topics described in the following table provide additional considerations for more specialized situations.

Topic	Description
Passing Objects as Parameters	Describes how to pass objects as [in] parameters to queued components.
Security Limitations in Workgroup Mode	Describes limitations on the use of Message Queuing authentication in workgroup mode.
Threading Considerations	Describes specific concerns related to passing recorder interface pointers between threads.
Receiving a Response	Describes how to construct a response to a queued component call.