using System;

​

public class Program

{

    public static void Main()

    {

        Parent p = new Parent()

        {

            Name = "Parent",

            Child = new Child()

        };

        Console.WriteLine(p.Child.Parent.Name);

    }

    public class Parent

    {

        public string Name {get; set;}

        public Child Child {

            get { return this._child; }

            set { 

                this._child = value; 

                if(value != null) 

                    value.Parent = this;

            }

        }

        private Child _child;

    }

    public class Child 

    {

        public Parent Parent {get; set;}

    }

​

}