Question

I have a class:

    public class Person
{
    public string FirstName { get; private set; }
    public string LastName { get; private set; }
    public string Email { get; private set; }
    public string Telephone { get; private set; }
    public Address Address { get; private set; }

    public Person(string firstName, string lastName)
    {
        //do null-checks
        FirstName = firstName;
        LastName = lastName;
        Address = new Address();
    }

    public void AddOrChangeEmail(string email)
    {
        //Check if e-mail is a valid e-mail here
        Email = email;
    }

    public void AddOrChangeTelephone(string telephone)
    {
        //Check if thelephone has correct format and valid symbols
        Telephone = telephone;
    }

    public void AddOrChangeAdress(Address address)
    {
        Address = address;
    }

The properties that are not in the constructor are optional, i.e. the person does not need an e-mail, address or telephone. However, I want to give the user of the class an opportunity to create the object without having to first provide the required information and then afterwards have to find out what methods to use to add the information.

Questions:

1. Is it right to create 3 additional overloads to give them that option?
2. Should i allow public setters on the optional properties and do the validation there?
3. If the person marries and changes last name, do I need additional method to change the last name or should I make this setter public too, and just require them in constructor?

Answer 1

1. No.
2. Yes
3. Make it public.

Assuming you are going to have more code in the AddOrChange methods such as formatting logic or validation then I’d do the following. Otherwise, I’d completely get rid of the AddOrChange methods:

public class Person
{
    private string _email = string.empty;
    private string _telephone = string.empty;
    private Address _address = new Address();

    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { 
        get { return _email }
        set { AddOrChangeEmail(value); }
    }
    public string Telephone { 
        get { return _telephone;}
        set { AddOrChangeTelephone(value); }
     }
    public Address Address { 
        get { return _address;  }
        set { AddOrChangeAddress(value); }
    }

    public Person(string firstName, string lastName)
    {
        //do null-checks
        FirstName = firstName;
        LastName = lastName;
    }

    private void AddOrChangeEmail(string email)
    {
        //Check if e-mail is a valid e-mail here
        _email = email;
    }

    private void AddOrChangeTelephone(string telephone)
    {
        //Check if thelephone has correct format and valid symbols
        _telephone = telephone;
    }

    private void AddOrChangeAddress(Address address)
    {
        _address = address;
    }
}

---

To work with this class you could do any of the following:

Person p = new Person("Tom", "Jones");
p.Telephone = "9995551111";

or

Person p = new Person("Tom", "Jones") { Telephone = "9995551111", Email="[e-mail]" }