VBA Class Module - Setting default values

I've only just started wrapping my head around building classes in Class Modules for VBA. It has been fairly smooth sailing so far, but I ran into a small challenge which is very easily solved if I were making a conventional function in a Module: How can I set an optional boolean default value to True?

In a function or sub, I would simply solve this in the property list by implicit declaration:

Function SomeFunction(Optional bValue = True) as Variant
...
End Function

In a Class Module using Let and Get properties, I haven't quite found my way around it yet since VBA defaultedly declares a Boolean variable as false. So I have, e.g.:

Private bValue as Boolean

Public Property Let TrueOrFalse(myBoolProperty As Boolean)
    bValue = myBoolProperty
End Property

Private Property Get TrueOrFalse() As Boolean
    TrueOrFalse = bValue
End Property

Function SomeFunction() As Boolean
    SomeFunction = TrueOrFalse
End Function

Bear in mind, I'm still learning, so even this simple code might be unsexy to the trained eye, but the question remains: How can I default bValue to True if I only want to use it as an Optional property?

Hopefully that made some sense..

Thank you for reading!

vbaexcel-vba

Answers

answered 4 years ago David Zemens #1

The Class_Initialize method will allow you to set default values.

I set up my properties like:

Option Explicit
Public pTrueOrFalse as Boolean

'## This method will be invoked whenever you create a class object using the NEW keyword/etc.
Private Sub Class_Initialize()
    pTrueOrFalse = True
End Sub

'## Property "Get" method, which returns the value when called
Public Property Get TrueOrFalse() As Boolean
    TrueOrFalse = pTrueOrFalse
End Property

'## Property "Let" method, which assigns the value when called
Public Property Let TrueOrFalse(lTrueOrFalse as Boolean)
    pTrueOrFalse = lTrueOrFalse
End Property

When using these in your regular code, you can do something like:

Dim myClassObject as New [class object name]   'this will invoke the Initialize procedure

MsgBox myClassObject.TrueOrFalse  'this will call upon the "Get" method

myClassObject.TrueOrFalse = False 'This will call upon the "Let" method

MsgBox myClassObject.TrueOrFalse

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