Getting Code Contracts to work in Visual Studio 2010

Question

I have the following code:

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine(SqrtRoot(0));
        Console.WriteLine(SqrtRoot(10));
        Console.WriteLine(SqrtRoot(-10));
        Console.ReadKey();
    }

    public static int SqrtRoot(int i)
    {
        Contract.Requires(i >= 0);
        return (int)Math.Sqrt(i);
    }
}

I am running it in debug mode, and it should fire some kind of error in the last line

Console.WriteLine(SqrtRoot(-10));

altough, for some reason, it doesn't. It seems to ignore the Contract.Requires() call. Should I set up something when trying to use Code Contracts?

I'm using Visual Studio 2010 RC.

Thanks

Answer 1

I don't have that tab either but I found a workaround:

Contract.Requires<ArgumentOutOfRangeException>(i >= 0);

Probably the code contracts package must be installed but the download link is not working. http://msdn.microsoft.com/en-us/devlabs/dd491992.aspx

Answer 2

You need to install the Visual Studio integration. While the CodeContracts library itself is part of .NET 4, your code needs to be rewritten by the Code Contracts rewriter (ccrewrite) to actually use the library properly.

Download the installer from the DevLabs site.

Answer 3

I think you have to enable runtime contract checking in the project settings (there should be a "Code Contracts" pane...)

See the user documentation (section 6) for further information.