7

I can't configurate Code Contracts in my class. I've followed the documentation and the example but it doesn't work.

I would to insert Code Contracts condition into my interface, here my code

The interface

 [ContractClass(typeof(ArticleBLLContract))]
 public interface IArticleBLL
 {
    int getArticleNSheet(string IdBox);
    IEnumerable<IArticle> getArticleValue(string IdBox, string IdLanguage);
}

The Contract Class

[ContractClassFor(typeof(IArticleBLL))]
public sealed class ArticleBLLContract : IArticleBLL
{
    int IArticleBLL.getArticleNSheet(string IdBox)
    {
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(IdBox),"IdBox has no valid value");                        

        return default(int);
    }

    IEnumerable<Base.Article.IArticle> IArticleBLL.getArticleValue(string IdBox, string IdLanguage)
    {
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(IdBox), "IdBox has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(IdLanguage), "IdLanguagehas no valid value");

        Contract.Ensures(Contract.Result<IEnumerable<Base.Article.IArticle>>() != null, "Return value is out of Range");

        return default(IEnumerable<Base.Article.IArticle>);
    }        
}

The class to apply Contract

public class ArticleBLL : IArticleBLL
{

    public int getArticlNSheet(string IdBox)
    {
        try
        {
            return _Dal...
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

    public IEnumerable<IArticle> getArticleValue(string IdBox, string IdLanguage)
    {
        IEnumerable<IArticle> article = null;

        try
        {
            article = _Dal...

            return article;

        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
}

I've tried to insert a breakpoint in this line

Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(IdBox),"IdBox has no valid value");

but when I call the method it never passes here This is my project configuration Code Contracts Config

Is there something wrong?

Thank you!

Faber
  • 2,194
  • 2
  • 27
  • 36

2 Answers2

4

Assembly Mode in your configuration should be "Standard Contract Requires".

Roy Dictus
  • 32,551
  • 8
  • 60
  • 76
  • I've read that setting "Standard Contract Requires" option the code contracts are not present into my released code, but I would to insert it also in my released code. Do I must set "Standard Contract Requires" option anyway? Thank You! – Faber Apr 13 '11 at 09:29
  • You can set the configuration differently for Debug and Release. So if you want contract validation in your Release build, you must set it there to "Standard Contract Requires" too. – Roy Dictus Apr 15 '11 at 08:41
  • To add: normally you would not need to verify requirements in a production environment. If in some cases bad input is expected, then you must handle that explicitly in your code. Code contracts are for verifying assumptions that should *always* be true. So, it is perfectly OK to have contracts in development, testing and acceptance environments, but I would not use them in the production environment. – Roy Dictus Apr 15 '11 at 08:43
3

Total re-write, based on comments so far

I've created a class library project, and put the interface and its contract class in there. I've set it to "Standard Contract Requires", runtime Pre and Post checks, and Build Contract Reference Assembly (I've set identical options for Debug and Release).

I've then got a console application, with a class implementing the interface, and set "Standard Contract Requires", runtime Pre and Post checks (again, set identically between Debug and Release).

Running it in either Debug or Release mode, I'm getting an ArgumentOutOfRangeException when trying to call getArticleNSheet.

With the obvious exception of switching to "Standard Contract Requires", what in the above doesn't match your current setup?

And, in fact, I was in error previously. With "Standard Contract Requires", I'm actually able to hit a breakpoint in the contract class, when debugging. I'm not sure by what Wizardry it's able to do this - since it isn't literally running the code in that class - as evidenced by the fact that you can re-write the method in the contract class as:

    int IArticleBLL.getArticleNSheet(string IdBox)
    {
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(IdBox), "IdBox has no valid value");

        throw new NotImplementedException();
    }

You can put a breakpoint on the Contract.Requires line, and it seems to hit it (after a warning about file mismatches, probably due to the re-writer). But assuming you've passed a non-empty string, it doesn't then throw a NotImplementedException.

Damien_The_Unbeliever
  • 234,701
  • 27
  • 340
  • 448
  • I've try to pass String.Empty in the method getArticleNSheet but any exceptions was raised. I've also try to change to non explicit implements of the interface but I've no exceptions raised. Is there anything wrong in the configuration? Thank you – Faber Apr 13 '11 at 13:47
  • @Faber - Assuming this is all in a single assembly, I also find that the contract doesn't seem to be checked. If I change the Contract Reference Assembly config to "Build", instead of "None", I then get warnings that I need to implement custom argument validation, or as Roy said, switch to "Standard Contract Requires" – Damien_The_Unbeliever Apr 13 '11 at 14:01
  • I've try to modify the configuration but it doesn't work. I've Interface and Contracts in a single assembly, but the class that implements the interface is in a different assembly. What is the best configuration to use Code Contracts with more assembly and keeping contracts also in released code? Thank you!! – Faber Apr 13 '11 at 15:01
  • @Faber - I've re-written my answer – Damien_The_Unbeliever Apr 14 '11 at 12:42
  • ...awesome...it's working!! I had not set Build Contract Reference Assembly. Thank you!!! – Faber Apr 14 '11 at 14:30