FAQ 34.35 What is a control container?

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An ActiveX control container is an application or component capable of hosting (or containing) an ActiveX control. Control containers must implement a mandatory set of COM interfaces for hosting and interacting with ActiveX controls. Control containers may also implement a number of optional COM interfaces, depending on the functionality they provide and the level of integration they wish to provide.

Control containers cannot rely on an ActiveX control supporting any specific interfaces other than IUnknown. Determining what interfaces an ActiveX control supports is part of the negotiation process that occurs between a control container and a control.

Control containers must degrade gracefully when an ActiveX control does not support a particular interface, even if this means it cannot perform its designated job. At a minimum, "degrade gracefully" means that the control container continues to operate and does not fail. As you can see, the ActiveX architecture assigns many responsibilities to the control container.

Some containers provide container-specific private interfaces for additional functionality or improved performance. Controls that rely on container-specific interfaces should also work without the container-specific interfaces so that the control can function in different containers.



C++ FAQs
C Programming FAQs: Frequently Asked Questions
ISBN: 0201845199
EAN: 2147483647
Year: 2005
Pages: 566
Authors: Steve Summit

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