using System;

​

public class Foo

{

    public Foo Parent;

    private int mFoobar;

    public void Test(){

        mFoobar = Parent.mFoobar;

    }

}

​

public class Program

{

    public static void Main()

    {

        var a = new Foo();

        var b = new Foo();

        a.Parent = b;

        a.Test();

    }

}