IExtenderProviderUnk Interface

The IExtenderProviderUnk interface derives from the IUnknown interface, while the IExtenderProvider derives from the IDispatch interface. Choosing which one to use is up to you and both are used by the extender mechanism, but the programming language you are using usually dictates which one of these interfaces you will implement. If you are using a language where IDispatch is not easily implemented, such as with Visual C++, then you may wish to implement the IExtenderProviderUnk interface. If you are using a language such as Visual C# or Visual Basic which will do the implementation of IDispatch for you (with the appropriate class attributes), then you can implement IExtenderProvider or IExtenderProviderUnk.