Class factory

[tiredofit]

This is taken from the following article:

https://datapluscode.com/general/no-constructor-no-problem/

It talks about class factories:

Option Explicit

Dim sColour As String

Public Property Let Colour(ByVal Value As String)

    sColour = Value

End Property

Public Property Get Colour() As String

    Colour = sColour

End Property

Private Sub Class_Initialize()

    sColour = "Red"

End Sub

Public Sub PrintColour()

    Debug.Print "The Car Colour is " & sColour

End Sub

When an object is created using this class, the class internally sets the colour of the car to be red when created. If we wanted to create a Car object which was blue, we would have to set its colour property to blue after creation:

My question is: why would you want to create a car object and set its colour property to be blue BEFORE creation?

 

[mikerickson]

One reason to set default properties in the Initialize event would be to avoid situations where a missing property would mess things up.
In your example, one can use class Cars and not worry that the color is "".

Another reason is if there are restrictions on the values that a property might have. Class Building might have a Height property, by setting a deault height (and by putting validation into the Property Let routine) one can confidently assume that .Height is never non-zero.

Setting up defaults is more often done when the property is an object, to avoid having to execute a If myObjectProperty Is Nothing in the code for the class.

 

[tiredofit]

Thanks for your explanation.