Passing data to overridden base method in C#

Question

Bit of a dumb question, but I'm wondering what the accepted way of passing data from back to an overridden base method is in c#.

e.g. I guess I could do:

class A
{
    int x;
    public virtual void DoStuff() {
        Console.WriteLine(x);
    }
}

class B : A
{
    public override void DoStuff() {
        x = 1;
        base.DoStuff();
    }
}

But is there a better method that for example doesn't require the use of a member variable?

I'm pretty sure I don't understand the question, but have you considered adding a method in the base class that takes a parameter instead? — Lasse V. Karlsen, Jun 11 '10 at 10:43

score 8 · Accepted Answer · answered Jun 11 '10 at 10:45

One solution can involve the use of a protected method that has an argument to reuse code from the base class.

class A
{
    public virtual void DoStuff() {
        DoStuffInternal(0);
    }
    protected void DoStuffInternal(int x) {
        Console.WriteLine(x);
    }
}

class B : A
{
    public override void DoStuff() {
        DoStuffInternal(1);
    }
}

score 2 · Answer 2 · answered Jun 11 '10 at 10:45

2

Why not use a parameter?

class A
{
    public virtual void DoStuff(int x) {
        Console.WriteLine(x);
    }
}

class B : A
{
    public override void DoStuff(int x) {
        //do stuff
        int y = 1
        base.DoStuff(y);
    }
}

answered Jun 11 '10 at 10:45

Maximilian Mayerl

11,253
2
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I don't want to expose the (int x) to consumers of B – UpTheCreek Jun 11 '10 at 10:47

score 2 · Answer 3 · answered Jun 11 '10 at 10:47

2

How about

abstract class A
{
    protected abstract int X { get; }
    public void DoStuff() {
        Console.WriteLine(X);
    }
}

class B : A
{
    protected override int X { get { return 1; } }
}

answered Jun 11 '10 at 10:47

Mark Heath

48,273
29
137
194

score 0 · Answer 4 · edited May 23 '17 at 12:01

You may use something like Template Method design pattern:

class A
{

    public void DoStuff() {
        var x = DoGetX();
        Console.WriteLine(x);
    }

    protected abstract int DoGetX();
}

class B : A
{
    protected override int DoGetX() {
      return 1;
    }
}

For almost every developer property is looks like simple wrapper around field, and we know that there are no such thing like virtual fields. So I think that abstract method is much more preferable solution in this case(we already discussed differences between properties and methods here).

Passing data to overridden base method in C#

4 Answers4