Method overrides cannot add preconditions.

hi
i've read thread on derived classes , have question
have abstract class hasn't property i've in derived class.
want use require contract on property.
how think implement this?

examle:

public abstract class  {       public abstract void methoda  }    public class b :  {      public dattime isa{get;set;}      public override void methoda()      {          contract.require(isa!=null);      }  }

hi,

alternatively, create abstraction preconditions moving them pure abstract method.  example:

(note: haven't tried compiling code)

[contractclass(typeof(acontracts))]  public abstract class  {      [pure]      protected abstract bool methodacanexecute();      public abstract void methoda();  }    [contractclassfor(typeof(a))]  public abstract class acontracts :  {     protected override abstract bool methodacanexecute();     public override void methoda()     {        contract.requires(methodacanexecute());     }  }    public class b :  {      public string isa { get; set; }      protected override bool methodacanexecute()      {          return isa != null;      }      public override void methoda()      {          // no additional preconditions necessary      }  }  

- dave

DevLabs  >  Code Contracts