Catching SQL unique key exceptions in .NET

I was wondering if anyone had a more elegant way to check for unique key exceptions from SQL in .NET other than parsing the error message? Right now I am calling the sproc in SQL, then using a try catch block in .NET. In the try catch block I parse the error message and it is a Unique key error I throw an instance of a custom error to the calling class, if not I just throw the original exception the the calling class. This seems awfully inefficient to me.

.Net Code Contracts – Where to learn more?

Runtime Checking. Our binary rewriter modifies a program by injecting    the contracts, which are checked as part of program> execution. Rewritten programs improve testability: each contract acts as an oracle, giving a test run a pass/fail indication. Automatic testing tools, such as Pex, take advantage of contracts to generate more meaningful unit tests by filtering out meaningless test arguments that don’t satisfy the pre-conditions.