Microsoft shipped the Composite Application Guidance for WPF formerly known as “Prism”. The Composite Application Guidance for WPF is designed to help you more easily build enterprise-level Windows Presentation Foundation (WPF) client applications. This guidance will help you design and build flexible composite WPF client applications—composite applications use loosely coupled, independently evolvable pieces that work together in the overall application.
Using the guidance streamlines the WPF team development experience. You can build solutions that take advantage of the full power of WPF and that are highly maintainable, testable, and whose pieces can be developed by separate teams.