C#: Is there a way to classify enums?

Question

Given the following enum:

    public enum Position
    {
        Quarterback,
        Runningback,
        DefensiveEnd,
        Linebacker
    };

Is it possible to classify the named constants, such that I could mark 'Quarterback' and 'Runningback' as offensive positions and 'DefensiveEnd' and 'Linebacker' as defensive positions?

Answer 1

You can use attributes:

public enum Position
{
    [OffensivePosition]
    Quarterback,
    [OffensivePosition]
    Runningback,
    [DefensivePosition]
    DefensiveEnd,
    [DefensivePosition]
    Linebacker
};

And then check for IsDefined on an appropriate FieldInfo. Syntax is not very pretty, but you can throw in a couple of extension methods to make things more manageble:

public static bool IsOffensivePosition(PositionType pt)
{
    return typeof(PositionType).GetField(Enum.GetName(typeof(PositionType), pt)).
        IsDefined(typeof(OffensivePositionAttribute), false);
}

Answer 2

You could use an attribute, like CategoryAttribute :

public enum Position
{
    [Category("Offensive")]
    Quarterback,
    [Category("Offensive")]
    Runningback,
    [Category("Defensive")]
    DefensiveEnd,
    [Category("Defensive")]
    Linebacker
};

Answer 3

Why not KISS:

class PlayerPosition {
    public enum Position {
        Quarterback,
        Runningback,
        DefensiveEnd,
        Linebacker
    }

    public enum Type {
        Offense,
        Defense
    }


    public static Type GetTypeForPosition(Position position) {
        switch (position) {
            case Quarterback:
            case Runningback:
                return Type.Offense;
            case DefensiveEnd:
            case Linebacker:
                return Type.Defense;

        }
    }
}