C# class design - what can I use instead of "static abstract"?

Question

I want to do the following

public abstract class MyAbstractClass
{
    public static abstract int MagicId
    {
        get;
    }

    public static void DoSomeMagic()
    {
        // Need to get the MagicId value defined in the concrete implementation
    }
}

public class MyConcreteClass : MyAbstractClass
{
    public static override int MagicId
    {
        get { return 123; }
    }
}

However I can't because you can't have static abstract members.

I understand why I can't do this - any recommendations for a design that will achieve much the same result?

(For clarity - I am trying to provide a library with an abstract base class but the concrete versions MUST implement a few properties/methods themselves and yes, there are good reasons for keeping it static.)

Answer 1

You fundamentally can't make DoSomeMagic() work with the current design. A call to MyConcreteClass.DoSomeMagic in source code will be translated into MyAbstractClasss.DoSomeMagic in the IL. The fact that it was originally called using MyConcreteClass is lost.

You might consider having a parallel class hierarchy which has the same methods but virtual - then associate each instance of the original class with an instance of the class containing the previously-static members... and there should probably only be one instance of each of those.

Answer 2

Would the Singleton pattern work perhaps? A link to the MSDN article describing how to implement a singleton in C#:

http://msdn.microsoft.com/en-us/library/ff650316.aspx

In your particular example, the Singelton instance could extend an abstract base class with your MagicId in it.

Just a thought :)