using System;

​

public class Program

{

    public static void Main()

    {

        var foo1 = new Foo{Bar = new Bar()};

        var foo2 = new Foo{Bar = (Bar)null};

        var foo3 = (Foo)null;

        Console.WriteLine("foo1: " + Convert(foo1));

        Console.WriteLine("foo2: " + Convert(foo2));

        Console.WriteLine("foo3: " + Convert(foo3));

    }

​

    static string Convert(Foo foo)

    {

        try

        {

            return foo?.Bar.ToString() ?? "<null>";

        }

        catch

        {

            return "exception!";

        }

    }

​

    class Foo

    {

        public Bar Bar

        {

            get;

            set;

        }

    }

​

    class Bar

    {

        public override string ToString()

        {

            return "bar";

        }

    }

}