would `as` enable polymorphism? would pass a inherited class to a method which takes a base class enable polymorphism?

Question

Fist of all, I will use virtual and override

for example, base class A has method A.do(), inherited class B has B.do() which overrides A's.

if I call (B as A).do(), which do() would it execute?

or, if there is a method void mymethod(A a) {a.do()}, now I call it by B b; mymethod(b), would it execute b.do()?

Answer 1

The most top override method always will be called, i.e. b.Do() or (b as A).Do() or ((A)b).Do() will call B.Do().

I don't know a way how to call a base method from child class if child class overrides it.