Question

So I only want to use one class Object for all of my functions but I do not want to directly use that class instead I need to access the members of the derived classes.

Take this example:

class A {
    public A() {

    }

    public void DoSomething() { }
}

class B : A {
    public B() {

    }

    public void DoSomethingBetter() { }
}

class C : A {
    public C() {

    }

    public void DoSomethingBest() { }
}

class Runner {
    public static void Main(String[] args) {
        A objB = new B();
        objB.DoSomethingBetter(); //Won't compile

        A objC = new C();
        objC.DoSomethingBest(); //Won't compile
    }
}

I don’t want to initialize them as B objB = new B(), that is not the purpose and I already know that that could be a solution. I need to just use the parent class for this.

Thanks

Answer 1

Not 100% sure what you’re trying to accomplish, but this is an option if for some reason you don’t want to override as others suggested.

class A {
    public A() {

    }

    public void DoSomething() { }
}

class B : A {
    public B() {

    }

    public void DoSomethingBetter() { }
}

class C : A {
    public C() {

    }

    public void DoSomethingBest() { }
}

class Runner {
    public static void Main(String[] args) {
        A objB = new B();
        if (objB is B)
            ((B)objB).DoSomethingBetter();

        A objC = new C();
        if (objC is C) 
            ((C)objC).DoSomethingBest();
    }
}

EDIT: A more efficient way to do this is as follows (it will run 2 casts instead of 4):

class A {
    public A() {

    }

    public void DoSomething() { }
}

class B : A {
    public B() {

    }

    public void DoSomethingBetter() { }
}

class C : A {
    public C() {

    }

    public void DoSomethingBest() { }
}

class Runner {
    public static void Main(String[] args) {
        A objB = new B();
        B objAB = objB as B;
        if (objAB != null)
            objAB.DoSomethingBetter();

        A objC = new C();
        C objAC = objC AS C;
        if (objAC != null) 
            objAC.DoSomethingBest();
    }
}