How to initialize a list with constructor?

Question

I have a type:

public  class Human
{
    public int Id { get; set; }
    public string Address { get; set; }
    public string Name { get; set; }
    public List         


        

Answer 1

Using a collection initializer

From C# 3, you can use collection initializers to construct a List and populate it using a single expression. The following example constructs a Human and its ContactNumbers:

var human = new Human(1, "Address", "Name") {
    ContactNumbers = new List() {
        new ContactNumber(1),
        new ContactNumber(2),
        new ContactNumber(3)
    }
}

Specializing the Human constructor

You can change the constructor of the Human class to provide a way to populate the ContactNumbers property:

public class Human
{
    public Human(int id, string address, string name, IEnumerable contactNumbers) : this(id, address, name)
    {
        ContactNumbers = new List(contactNumbers);
    }

    public Human(int id, string address, string name, params ContactNumber[] contactNumbers) : this(id, address, name)
    {
        ContactNumbers = new List(contactNumbers);
    }
}

// Using the first constructor:
List numbers = List() {
    new ContactNumber(1),
    new ContactNumber(2),
    new ContactNumber(3)
};

var human = new Human(1, "Address", "Name", numbers);

// Using the second constructor:
var human = new Human(1, "Address", "Name",
    new ContactNumber(1),
    new ContactNumber(2),
    new ContactNumber(3)
);

Bottom line

Which alternative is a best practice? Or at least a good practice? You judge it! IMO, the best practice is to write the program as clearly as possible to anyone who has to read it. Using the collection initializer is a winner for me, in this case. With much less code, it can do almost the same things as the alternatives -- at least, the alternatives I gave...