COM Shared Add-in (Part 2)

What are the Office XP Primary Interop Assemblies?

Component Object Model (COM) interop assemblies allow unmanaged (COM) code to be called from managed (.NET) code by using the Microsoft .NET Framework and the common language runtime. COM interop assemblies allow managed applications to bind to unmanaged types at compile time and provide information to the common language runtime about how the unmanaged types should be marshaled at run time.

While any number of COM interop assemblies may exist for a given type library, only one COM interop assembly is designated as the primary interop assembly (PIA). The PIA contains the official description of the unmanaged types as defined by the publisher of those unmanaged types. The PIA usually also contains certain customizations that make the types easier to use from managed code. The PIA is always digitally signed by the publisher of the original unmanaged type.

The details on How to install and Reference XP PIa's ? will be continued on the next post...