Calling child class constructor before parent constructor

Question

Is it possible to call the constructor of child class before the constructor of the parent class?

Someone said it is indeed possible with the use of a virtual method, but I can't find a way to do so.

Answer 1

In IL, this is possible. In C#: no.

You can use virtual to run a method in a type before that type's ctor, but it is discouraged and risky. But:

class Foo {
    public Foo() {
        Console.WriteLine("Foo ctor");
        SomeMethod(); // BAD IDEA (calling a virtual method in a ctor)
    }
    protected virtual void SomeMethod() {}
}
class Bar : Foo {
    protected override void SomeMethod() {
        Console.WriteLine("SomeMethod in Bar");
    }
    public Bar() : base() { /* only to show call order */
        Console.WriteLine("Bar ctor");
    }
}

It is a bad idea because you can't guarantee that the subclasses are ready for the method-call.