A typical WPF application is made up of many pieces. Making sure you don't have references from one piece to another is key to developing any application. User controls and a good messaging system should be the backbone of your WPF applications. Each piece of a WPF window should be built with individual user controls and view models. In this seminar, you create user controls, combine them together, and see how to communicate between them. Creating your WPF applications in this manner takes full advantage of loose coupling principles. Loose coupling makes your application more robust, reusable, maintainable and testable. This seminar shows an application with multiple pieces on a window and how they all interact together, but with no coupling between them.