In this interview with Joe Binder, a Program Manager on the LightSwitch team, we discuss the LightSwitch application framework architecture and how a LightSwitch application is built on top of well-known technologies like Silverlight, MVVM, RIA Services, and Entity Framework. Joe shows us how to modify the behavior of a screen and how it exposes the commanding pattern in an easy-to-use way. He also shows us how to extend the UI with our own custom Silverlight controls, as well as how to connect our own data sources using RIA Services.   For an introduction to LightSwitch please see this interview: Jay Schmelzer: Introducing Visual Studio LightSwitch For more information on LightSwitch, please see: Visual Studio LightSwitch Developer Center Visual Studio LightSwitch Team Blog Visual Studio LightSwitch Forums   Enjoy, -Beth Massi, Visual Studio Community