best way to create object

Question

This seems to be very stupid and rudimentary question, but i tried to google it, but couldn't a find a satisfactory answer,

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public Person(){}
    public Person(string name, int age)
    {
        Name = name;
        Age = age;
    }
    //Other properties, methods, events...
}

My question is if i have class like this, what is the best way to create an object?

Person p=new Person("abc",15)

OR

Person p=new Person();
p.Name="abc";
p.Age=15;

What is the difference between these two methods and what is the best way to create objects?

Answer 1

In my humble opinion, this is just a matter of deciding if the arguments are optional or not. If an Person object shouldn't (logically) exist without Name and Age, they should be mandatory in the constructor. If they are optional, (i.e. their absence is not a threat to the good functioning of the object), use the setters.

Here's a quote from Symfony's docs on constructor injection:

There are several advantages to using constructor injection:

• If the dependency is a requirement and the class cannot work without it then injecting it via the constructor ensures it is present when the class is used as the class cannot be constructed without it.
• The constructor is only ever called once when the object is created, so you can be sure that the dependency will not change during the object's lifetime.

These advantages do mean that constructor injection is not suitable for working with optional dependencies. It is also more difficult to use in combination with class hierarchies: if a class uses constructor injection then extending it and overriding the constructor becomes problematic.

(Symfony is one of the most popular and respected php frameworks)