Force base method call

Question

Is there a construct in Java or C# that forces inheriting classes to call the base implementation? You can call super() or base() but is it possible to have it throw a comp

Answer 1

The following example throws an InvalidOperationException when the base functionality is not inherited when overriding a method.

This might be useful for scenarios where the method is invoked by some internal API.

i.e. where Foo() is not designed to be invoked directly:

public abstract class ExampleBase {
    private bool _baseInvoked;

    internal protected virtual void Foo() {
        _baseInvoked = true;
        // IMPORTANT: This must always be executed!
    }

    internal void InvokeFoo() {
        Foo();
        if (!_baseInvoked)
            throw new InvalidOperationException("Custom classes must invoke `base.Foo()` when method is overridden.");
    }
}

Works:

public class ExampleA : ExampleBase {
    protected override void Foo() {
        base.Foo();
    }
}

Yells:

public class ExampleB : ExampleBase {
    protected override void Foo() {
    }
}