AddressHistoryEntity.AddressValue address = addressHistory.AddressHistory.EnumerateItems().FirstOrDefault();

​

var personDetails = PersonDetailsEntity.Create(

    primaryName: person.PrimaryName.As<PersonDetailsEntity.PersonNameValue>(),

    address: address.IsNotNullOrUndefined() ? 

        PersonDetailsEntity.AddressValue.Create(

            line1: address.Line1.AsOptional(),

            line2: address.Line2.AsOptional(),

            line3: address.TownOrCity.AsOptional(),

            line4: address.Region.AsOptional(),

            postalCode: address.PostalCode.AsOptional()) : null);

​

using System;

​

class Program

{

    static void Main(string[] args)

    {

        Console.WriteLine("Hello World!");

    }

}

You typed to many # like myself.