T4 is a template-based code generation engine included in Visual Studio 2005, 2008 and 2010. This engine could be used to generate any text based file. VS.NET uses this engine to turn project types and item types in items within your project. In this session you'll be introduced to T4 directives, how to create a T4 file in Visual Studio and write a sample app to generate C# code and compile it on the fly.