Reputation: 155

What is it called when a class property is an instance of another class?

Very basic question here, look at my property Order in my customer class. Wondering what is the formal name of a property type like this is (yes, this could also be a list).

public class Customer
{
    public int ID { get; set; }
    public string Name { get; set; }

    public Order Orders { get; set; }  // what am i called?
}

public class Order
{
    public int ID { get; set; }
    public string SomeProperty { get; set; }
}

Upvotes: 0

Answers (5)

Patrick M

Reputation: 93

The concept itself is called Composition. Basically, you want to be able to use a Customer object to get information about an Order, but you don't want the logic that gets that information to live in Customer. So, you have a member who is an Order and Order encapsulates the Order behavior.

You could say that a Customer is composed of Order along with other values.

Have a link: http://www.javaworld.com/jw-11-1998/jw-11-techniques.html

Not that you asked this, but you probably will want an actual collection of Orders. You could start with
public List<Order> Orders;

Upvotes: 1

Habib

Reputation: 223322

Its the same thing. Its called a "Property". There is no different name for it. Consider your SomeProperty which is of type string. string is also a class and SomeProperty is its object. Same convention with your class would follow as well.

From C# Language Specification.

1.6.7.2 Properties

A property is declared like a field, except that the declaration ends with a get accessor and/or a set accessor written between the delimiters { and } instead of ending in a semicolon.

So the term "property" in C# is associated with the accessors (get/set)

Upvotes: 4