Add-ins and Extensibility

Add-ins provide extended features or services for a host application. The .NET Framework provides a programming model that developers can use to develop add-ins and activate them in their host application. The model achieves this by constructing a communication pipeline between the host and the add-in. The model is implemented by using the types in the System.AddIn, System.AddIn.Hosting, System.AddIn.Pipeline, and System.AddIn.Contract namespaces.

For additional code samples, and customer technology previews of tools for building add-in pipelines, see the Managed Extensibility and Add-In Framework site on CodePlex.

In This Section

• Add-in Overview
  Describes the add-in programming model for the .NET Framework.

• Pipeline Development
  Describes the communication pipeline of segments from the host application to the add-in. Provides code examples in walkthrough topics that describe how to construct the pipeline and how to deploy segments to the pipeline in Visual Studio.

• Add-in Discovery
  Describes how to make add-ins discoverable by host applications.

• Add-in Activation
  Describes how to activate and deactivate add-ins.

• Add-In Performance
  Describes how to use domain-neutral assembly loading and native images to improve add-in performance.

• How to: Activate Add-ins with Different Isolation and Security Levels
  Describes how to activate add-ins in a variety of application domain, process, and security-level scenarios.

• How to: Use Qualification Data
  Describes how to apply and access custom data attributed to add-ins and pipeline segments.

• Add-in Developer Experience
  Describes how to develop an add-in to use the required segments of the add-in pipeline.