In Visual Studio 2005 and prior you could export your code to Visio and view the relationships between the objects and what methods, properties and fields it had. This was great
Not your answer, but related...
Codeplex's VisioAutoExt library: http://www.codeplex.com/visioautoext
Visio ActiveX component: http://www.c-sharpcorner.com/UploadFile/mgold/VisioInDotNet12032006222024PM/VisioInDotNet.aspx