Question

I’m designing a new application and I’m undecided if I should fill my object properties on the constructor

Public Sub New(UserId as integer)     ' get database values     dr = DataReader     Me.FirstName = dr.fields(0)     Me.LastName = dr.fields(1) End Sub 

Or create a factory with a method for each object type?

Public Function getUser(UserId as integer) as User     Dim myUser as new User     ' get database values     dr = DataReader     myUser.FirstName = dr.fields(0)     myUser.LastName = dr.fields(1)     return myUser End Function 

I realize that the code is rough, but I’m hoping it’s enough to get my point across. I’ve see both implemented and not sure what the long term pros and cons are.

Specifically, I’m using VB.NET, if it matters.

Answer 1

My opinion:

A constructor creates an object. The constructor of a User class should create a new user.

Static member functions like your getUser retrieve an object which already exists.

I would use the latter form.