Person.Builder.Build C# (CSharp) Method

        public Person Build()
        {
            var ret = Underlying;
            ((FreezableList<PhoneNumber>) ret.Phones).Freeze();
            underlying = null;
            return ret;
        }
    }

        /// <summary>
        /// Builds a person based on user input
        /// </summary>
        static Person PromptForAddress(TextReader input, TextWriter output)
        {
            Person.Builder person = Person.CreateBuilder();

            output.Write("Enter person ID: ");
            person.Id = int.Parse(input.ReadLine());

            output.Write("Enter name: ");
            person.Name = input.ReadLine();

            output.Write("Enter email address (blank for none): ");
            string email = input.ReadLine();

            if (email.Length > 0)
            {
                person.Email = email;
            }

            while (true)
            {
                output.Write("Enter a phone number (or leave blank to finish): ");
                string number = input.ReadLine();
                if (number.Length == 0)
                {
                    break;
                }

                Person.Types.PhoneNumber.Builder phoneNumber =
                    Person.Types.PhoneNumber.CreateBuilder().SetNumber(number);

                output.Write("Is this a mobile, home, or work phone? ");
                String type = input.ReadLine();
                switch (type)
                {
                case "mobile":
                    phoneNumber.Type = Person.Types.PhoneType.MOBILE;
                    break;

                case "home":
                    phoneNumber.Type = Person.Types.PhoneType.HOME;
                    break;

                case "work":
                    phoneNumber.Type = Person.Types.PhoneType.WORK;
                    break;

                default:
                    output.Write("Unknown phone type. Using default.");
                    break;
                }

                person.AddPhone(phoneNumber);
            }
            return(person.Build());
        }