How can you override an enum in C#?

Question

This is my code:

void Main()
{
    StarTrek baseClass = new StarTrek();
    NewGeneration childClass = new NewGeneration();

    baseClass.ShowEnum();
    childClass.ShowEnum();
}

public class StarTrek
{
    internal enum Characters
    {
        Kirk, Spock, Sulu, Scott
    }

    public void ShowEnum()
    {
        Type reflectedEnum = typeof(Characters);
        IEnumerable<string> members = reflectedEnum.GetFields()
                                            .ToList()
                                            .Where(item => item.IsSpecialName == false)
                                            .Select(item => item.Name);
        string.Join(", ", members).Dump();
    }
}

public class NewGeneration : StarTrek
{
    internal new enum Characters
    {
        Picard, Riker, Worf, Geordi
    }       
}

ShowEnum always displays:

Kirk, Spock, Sulu, Scott

even if it was called in the NewGeneration class. Am I missing/misunderstanding something? Is there a way for ShowEnum to use the NewGeneration.Characters instead of StarTrek.Characters?

Answer 1

Your second enum is shadowing the first one, in just the same way as declaring a new field within NewGeneration would. Nested types aren't polymorphic - the code in ShowEnum will always refer to StarTrek.Characters; the code is built against that type at compile-time.

It's not really clear what you're trying to do, but you definitely can't do it in the way that you're trying. If you want polymorphic behaviour you have to be using methods, properties or events, which must then be declared virtual in order to be overridden in the derived class.

(It's worth noting that overloading and overriding are different, by the way - your question refers to overloading but I think you meant overriding.)