Extensibility Terminology

  • Host An application that supports extensibility. A host may be a client or server (for example, Excel, Word, Paint.NET, SQL Server, and Exchange Server).
  • Extensibility A mechanism for manipulating host application objects or extending host functionality, sometimes referred to as automation. Generally made available via an object model published as part of a host’s SDK
  • Software Development Kit (SDK) A set of public interfaces (APIs) and associated documentation. Allows the host application to provide services to an add-in and vice versa. This SDK may be provided by different parties in different situations. For example, the host may provide the SDK to enable host-specific add-ins, an add-in may provide the SDK to let many different hosts use it (for example, Windows Media® Player), a third party may provide the SDK to let many different hosts, and add-ins communicate with each other.
  • Add-In (also called Add-On, Extension, Plug-In, Snap-In) A customization; an assembly loaded by a host. Also, something that automates a host application (such as a client). Something that provides additional functionality to a host (service). An add-in is custom code, usually written by a third party, that is dynamically loaded and activated, by a host application, based upon some context (such as host startup or document loading). The add-in extends the host application via the host’s public API (for example, an object model or managed class library) which was made available to the add-in via an SDK.
  • Pipeline The machinery that enables the host and add-in to communicate over a version-resilient, secure protocol.

Resource

  1. CLR Inside Out: .NET Application Extensibility part 1 & part 2 : The first pages you should read when study System.AddIn namespace.
  2. CLR Add-In Team Blog: All about the CLR’s System.AddIn model for managed add-ins, add-ons, plug-ins, and extensions. Where you can study, discussion and understand some intenal implement of System.AddIn.
  3. System.AddIn Tools and Samples: Where you can download tools and samples. Post a question or discussion about System.AddIn.