C# Use base class property value in a derived class property override

Question

My class structure is as follows:

public class Animal
{
    private int _animalId;

    public virtual int AnimalId
    {
        get { return _animalId; }
    }
}

public class Dog : Animal
{
    public override int AnimalId
    {
        get 
        { 
            if (Request.Params["New_Animal"] == "true")
                return -1;
            else
                return AnimalId;
        }
    }
}

I would like to override the AnimalId property as follows: if it is a new animal the id should be -1, but if we are updating an existing animal I would like to return the AnimalId from the base class.

This is an extremely simplified example, but I'm wondering if / how this can be done.

Thanks

When you say you want to update an existing animal, do you mean to retrieve it from a database? Or do you mean that after a property is changed, the animal is no longer new and so therefore you want it to no longer have an Id of -1? — Jonathan Walton, Oct 10 '18 at 20:09
@JonathanWalton update as in retrieve the record from database and update the data, and new as in inserting a new record into the database — full-stack, Oct 10 '18 at 20:13
it sounds a little bit like inheritance is not the correct approach for you. Are you counting the animals? sounds like you need a static variaable — Mong Zhu, Oct 10 '18 at 20:13
@MongZhu as I stated in my question, this is an extremely simplified example, but I will look into it and see if that is a viable option. — full-stack, Oct 10 '18 at 20:15
what is the inheritance relationship good for ? I don't understand the connection to the database records — Mong Zhu, Oct 10 '18 at 20:28
My page must inherit from the parent because there are many other methods and properties that are used. Once I'm already inheriting why should I create my own independent static property which will be using a value from the parent page. — full-stack, Oct 10 '18 at 20:32
ok now the picture gets clearer in my mind. Ok then my comment is useless. thanx for the clarification — Mong Zhu, Oct 10 '18 at 20:36

score 4 · Accepted Answer · answered Oct 10 '18 at 20:42

Use base.AnimalId

public class Animal
{
    private int _animalId;

    public virtual int AnimalId
    {
        get { return _animalId; }
    }
}

public class Dog : Animal
{
    public override int AnimalId
    {
        get 
        { 
            if (Request.Params["New_Animal"] == "true")
                return -1;
            else
                return base.AnimalId;
        }
    }
}

juliushuck · Answer 2 · 2018-10-10T21:59:18.107

0

You can make the animalId in animal private protected and in dog you can then return base.animalid in the property

edited Oct 10 '18 at 21:59

answered Oct 10 '18 at 20:09

juliushuck

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C# Use base class property value in a derived class property override

2 Answers2