Is there a free tool that can create class diagrams for us? We want to run this on a solution and have the software generate a complete diagram of the classes and inter relationships for us. A UML - like diagram would be best. We currently have VSTS 2008 and it would be great if this was built in.
You can create class diagrams inside Visual Studio. Just select New item > Class diagram from the project menu.
Visual studio has it's own uml designer. Just add a class diagram to your project and drag and drop the classes you want.
In VS2008 you can actually create "UML" diagrams. It's directly integrated, when you right-click on your VS project. It's not real UML, so I don't know if it suits you needs.
Anyway I wonder for what reason you need a class diagram of your whole program? From my personal experience I didn't find it useful to model whole applications as UML class diagrams. They are more useful to model relationships among parts of an application for a better understanding between the devs.
Actually, Visual Studio 2010 Ultimate has support for UML class, sequence, component, use case, and activity diagrams. The 2008 Class Designer will still be included, but the team is working on reverse-engineering UML class diagrams from code in a future release.
For more info, see this thread in the VS Architecture & Modeling tools forum: Is it possible to reverse engineer C# code into an UML Class Diagram?
You'll also be able to use new code visualization and exploration tools such as generating sequence, dependency graphs, and layer diagrams from code. You can link UML diagrams to Team Foundation work items and extend your UML models.
I've posted more links on my profile for more info.