I have the following code creating an instance of Root
using an object-initializer:
var r = new Root { Person = new Person { Age = 20, Name = "Hans" } };
From Is there any benefit of using an Object Initializer? I know if we´d have only the inner object Person
this was translated to something like this:
var p = new Person();
p.Age = 20;
p.Name = 20;
What I wonder is how does this affect the nested objects in my first example? Is Person
completely created and than assigned to the new instance of Root
or is this merely translated to something like this:
var r = new Root();
r.Person = new Person();
r.Person.Age = 20; // this would call the Persons getter
r.Person.Name = "Hans"; // this would call the Persons getter
The reason I ask is that the getter and setter to modify a Person
for a given Root
is quite complex and I´d like to avoid to call its getters for the sake of setting the properties for that Person
.
This is explicitly addressed in 7.6.10.2 of the C# Language Specification.
The standard gives this example for a "nested object initializer":
public class Point
{
int x, y;
public int X { get { return x; } set { x = value; } }
public int Y { get { return y; } set { y = value; } }
}
public class Rectangle
{
Point p1, p2;
public Point P1 { get { return p1; } set { p1 = value; } }
public Point P2 { get { return p2; } set { p2 = value; } }
}
Rectangle r = new Rectangle
{
P1 = new Point { X = 0, Y = 1 },
P2 = new Point { X = 2, Y = 3 }
};
The standard says that this has the same effect as:
Rectangle __r = new Rectangle();
Point __p1 = new Point();
__p1.X = 0;
__p1.Y = 1;
__r.P1 = __p1;
Point __p2 = new Point();
__p2.X = 2;
__p2.Y = 3;
__r.P2 = __p2;
Rectangle r = __r;
Here you can see that the Rectangle.P1
and Rectangle.P2
properties are initialised from already-created Point
objects.
This proves that the answer to your question
Is Person completely created and than assigned to the new instance of Root?
is definitively: Yes.