Pro WPF in C# 2010: Windows Presentation Foundation in .NET 4

32.2. The Add-in Pipeline

The key advantage of the add-in model is that you don't need to write the underlying plumbing for tasks such as discovery. The key disadvantage is the add-in model's sheer complexity. The designers of .NET have taken great care to make the add-in model flexible enough to handle a wide range of versioning and hosting scenarios. The end result is that you must create at least seven (!) separate components to implement the add-in model in an application, even if you don't need to use its most sophisticated features.

The heart of the add-in model is the add-in pipeline, which is a chain of components that allow the hosting application to interact with an add-in (see Figure 32-1). At one end of the pipeline is the hosting ...