what is Primary Interop Assembly (PIA)?

Question

hi Please tell me what is Primary Interop Assembly (PIA)?

Vulpes · Answer

AFAIK the term PIA is only used in the context of COM and is a managed library which contains type definitions for interoperating with COM types. Before .NET 4.0 you had to reference the whole of a PIA in order to use any COM type within it. This was a nuisance because PIA's are typically huge (notably the MS office ones) and the whole library needed to be loaded even if you were only actually using a small part of its functionality. In .NET 4.0 there is the default option of linking to the PIA instead. This means that don't need to deploy the PIA because the parts of it which you actually use are embedded directly into your application.

Dipal Choksi · Answer

In Microsoft's words: Like any other managed assembly an interop assembly is a collection of types that are deployed versioned and configured as a single unit. However unlike other managed assemblies an interop assembly contains type definitions (not implementation) of types that have already been defined in COM. These type definitions allow managed applications to bind to the COM types at compile time and provide information to the common language runtime about how the types should be marshaled at run time.  A PIA is typically a wrapper dll which exposes functions in a non-managed dll allowing your managed application (.net application) to access functionality within the non-managed dll.

Javeed M Shaikh · Answer

its a third party assembly which contains type definitions of types implemented in that.