c＃阻止了方法的继承

Question

For a poker parser (my first project for learning c#), I have a parent class clCardsHeld and two child classes clHiHand and clLoHand . clCardsHeld also contains properties and private fields, of each of the two child types. And so what I end up with, with this inheritance, is, eg:

public class clCardsHeld
{public clHiHand HiHand { Get {} Set {} }
} 
public class clHiHand : clCardsHeld{}

clCardsHeld Hand3 = new clCardsHeld(); 
clHiHand hi = new clHiHand(); 
hi = Hand3.HiHand.HiHand.HiHand; 
hi = Hand3.HiHand.LoHand.HiHand;

(as prompted by intellisense). ( HiHand shouldn't have another HiHand as a property of itself, nor a low hand. But CardsHeld has a HiHand and LoHand as properties in, eg, games where you get 7 cards and you can use 5 to make to best possible hand and 5 for the worst possible, both played at the same time, for half the pot each.)

I made the base class fields private, instead of protected, so the inherited property remains null , if I've discerned that correctly. But really I'd like the property not to be inherited. Trying to research this, I see that a property can only be sealed when it overwrites a base property. And "hiding" the method generally refers to having different code in the child... .

One other thing, while I'm throwing out my novice questions:

    public class clCardsHeld { private List<clCards> _liCards; }
public class clHiHand : clCardsHeld 

I can find clCardsHeld._liCards in the locals window, but I can't find clCardsHeld.clHiCards._liCards in the locals window (but I can get at it by assigning it to a variable.

Thanks for any help.

Answer 1

As mentioned in the link referenced by Adeel, the inheritance in this situation is unnecessary. Your high hand and low hands should just be new instances of clCardsHeld:

public class clCardsHeld
{
    private List<clCards> _liCards;

    public clCardsHeld GetLoHand()
    {
        //Logic here for returning the low hand, using _liCards
    }

    public clCardsHeld GetHiHand()
    {
        //Logic here for returning the high hand, using _liCards
    }
}

The GetLoHand() and GetHiHand() functions will simply return a different set of held cards.

Answer 2

There are a couple of misconceptions in your post..

• If you want a property not to be inherited, you are violating the Liskov Substitution Principle .
• Fields are not null in a subclass just because they are private to the base class. They can still be assigned by the logic in the base class.
• It sounds to me like you are using inheritance when you don't need to.. Use inheritance when a concept (subclass) is a special case of another concept (base class). And favor composition over inheritance.

I think you should split what is common to all the objects into a separate base class:

class HandBase { /* common to both HiHand an LoHand */}
class LoHand : HandBase {}
class HiHand : HandBase {}

From what I can tell from your explanation, cCardsHeld does not have to have the same base type:

class CardsHeld
{
    public LoHand LoHand { get; private set;}
    public HiHand HiHand { get; private set;}
}

But if it does, then you could do this:

class CardsHeld : HandBase
{
    public LoHand LoHand { get; private set;}
    public HiHand HiHand { get; private set;}
}

If there is a property that you don't want subclasses to have, then don't put it in the base class.