T4 is used more for codegen; or, you can write a code-generator plugin for Visual Studio to handle a specific type of code generation (e.g., where you can expan

T4 is used more for codegen; or, you can write a code-generator plugin for Visual Studio to handle a specific type of code generation (e.g., where you can expand a file in the solution/project pane and see the 'code-behind'). Most of the codegen for MS tools actually generates code in whatever language your project uses (like C#). CCI is a library for manipulating .NET bytecode, and is much lower-level than you'd normally need (or want) to deal with.