CODEWITHSUNDEEP
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Didaxis
Didaxis

Reputation: 8746

Can members of an inner class be overridden?

Suppose you have the following class declarations:

public abstract class Foo
{
    public class Bar
    {
        public virtual void DoSomething() { ... }
    }
}

Is it possible to override Bar.DoSomething() in a child class of Foo, a la:

public class Quz : Foo
{
    public override void Bar::DoSomething() { ... }
}

Obviously that syntax doesn't work, but is something like this possible?

Upvotes: 2

Views: 555

Answers (3)

myermian
myermian

Reputation: 32515

No, but you can still inherit from the Foo.Bar class itself:

public class BarDerived : Foo.Bar
{
    public override void DoSomething() { ... }
}

I feel I should explain that doing this will not mean that a class deriving from Foo will all of a sudden have an inner class of BarDerived instead, it just means that there is a class that can be derived from it. There are ways of replacing what type of class you want to use as the inner class, for example:

public class Foo<T>
    where T : Foo.Bar
{
    private T _bar = new T();

    public class Bar
    {
        public virtual void DoSomething() { ... }
    }
}

public class BarDerived : Foo.Bar
{
    public override void DoSomething() { ... }
}

public class Quz : Foo<BarDerived> { ... }

Upvotes: 6

Tomer W
Tomer W

Reputation: 3443

Well, if you are following good practices, then the Bar cannot be constructed by any other class then Foo, that said enables the following:

Create a derived class from Foo::Bar in Quz, and override it's DoSomething()
override each method in Foo where Bar is constructed and provide the derived class instead.

the user of Foo should not know the difference in API between Bar and your new derived inner class.

hope this makes sense.

Upvotes: 0

Selman Gen&#231;
Selman Gen&#231;

Reputation: 101701

No, only if you inherit from Bar

public class Quz : Foo.Bar
{
    public override void DoSomething() { ... }
}

Upvotes: 1

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