using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("new BaseOuter");

        var baseOuter = new BaseOuter();

        Console.WriteLine("\nnew DerivedOuter");

        var derivedOuter = new DerivedOuter();

    }

    class BaseOuter{

        protected BaseInner baseInner;

        public BaseOuter(){

            Console.WriteLine("BaseOuter Constructor");

            /*  lots of stuff I want in derived class */

​

            // This is an anti-pattern I want to avoid

            //https://www.jetbrains.com/help/resharper/2018.2/VirtualMemberCallInConstructor.html

            InitializeInner();

        }

        protected virtual void InitializeInner(){

            Console.WriteLine("    BaseOuter Initialize BaseInner");

            baseInner = new BaseInner();

        }

        protected class BaseInner{

            public int x;

            public BaseInner(){

                /* stuff that is needed in DerivedInner too */

                Console.WriteLine("        BaseInner Constructor");

                x = 2;

            }

        }       

    }

    class DerivedOuter : BaseOuter {

        public DerivedOuter() {

            Console.WriteLine("DerivedOuter Constructor (finished)");

        }

        protected override void InitializeInner(){

            Console.WriteLine("    DerivedOuter Initialize DerivedInner");

            baseInner = new DerivedInner();

        }

​

        protected class DerivedInner : BaseInner {

            public double y;

            public DerivedInner(){

            Console.WriteLine("        DerivedInner Constructor");

                y = 2d;

            }

        }

    }

}