using System;

public class Program

{

    public static void Main()

    {

        var Model = new Model

        {

            Model2 = new Model2

            {

                Model3 = new Model3

                {

                    Model4 = new Model4()

                }

            }

        };

        Console.WriteLine("Name is null: {0}", Model.Model2.Model3.Model4.Name == null);

        var name = Model.Model2?.Model3?.Model4?.Name ?? "N/A";

​

        Console.WriteLine(name);

        /* This is the first example */

        if (Model.Model2 == null

            || Model.Model2.Model3 == null

            || Model.Model2.Model3.Model4 == null)

        {

            Console.WriteLine("N/A");

        }

        else

        {

            Console.WriteLine("Should print N/A");

            Console.WriteLine(Model.Model2.Model3.Model4.Name);

            Console.WriteLine("...but has not");

        }

    }

    public class Model

    {

        public Model2 Model2 { get; set; }  

    }

    public class Model2

    {

        public Model3 Model3 { get; set; }  

    }

    public class Model3

    {

        public Model4 Model4 { get; set; }  

    }

    public class Model4

    {

        public string Name { get; set; }    

    }

}

​