Continuing his great work on Software Contracts from the April 2011 issue of MSDN Magazine  Dino Esposito, in the May 2011 issue, Dino shows how to set-up code contracts in Visual Studio 2010. 

In this article Dino now asks the question and guides you to the answers of whether to use code or software contracts in design or debug mode.  The use of contracts is baked into the Framework and not part of any specific language.  In this case read: Code Contracts Settings in Visual Studio 2010 for how to set up Code Contracts and in what mode. 

For more information about code contract that isn’t quite as extensive as Dino’s excellent work can be found at:

Another source is from Microsoft Research: