Reegenerator achieves that through three simple ideas:
Use a standard Visual Studio project to host/author/build the code generators. Consequently everything is where you expect it to be: the editors, code behind, debugging, integrated help, source control, your favourite tools, use of external libraries and so on.
Transparently link any project item belonging to the solution to the code generators so that they trigger the code generation process when saved within Visual Studio.
Allow code generators to access Visual Studio's information regarding the solution you generate code for (same as Class View).
Because of the unique approach, Reegenerator offers all the features you would expect plus these unique ones:
Outstanding integration (debugging, help, source control and much more) and very low learning curve.
Customize the code generated by standard designers (e.g. LINQtoSQL, Resources or Settings). Article
Generate code from code (manually written code can generate other code. Ideal for implementing certain patterns).
Generate code from any type of file (e.g. generate code from Word or Excel business requirements documents).