Initializing Object with Arrays VBA

Question

I'm trying to create a class with arrays in it, and I'm having issues creating the class for it...

CLASS:

Private pST(0 To 2) As String

Public Property Get ST() As String
   ST() = pST()
End Property
Public Property Let ST(value() As String)  '<---- ERROR HERE
   pST() = value()
End Property

CODE RUN:

Sub test()

   Dim foo As cPurchaseOrder
   Set foo = New cPurchaseOrder

   foo.ST(0) = "test"

   Debug.Print foo.ST(0)

End Sub

THE ERROR:

Compile error:

Definitions of property procedures for the same property are inconsistent, or property procedure has an optional parameter, a ParamArray, or an invalid Set final parameter.

THE QUESTION:

How can I properly initialize a class with arrays as variables?

EDIT: in relation to Mat's Mug response

CLASS CHANGED:

Private pST As Variant

Public Property Get STContent(ByVal index As Long) As String
    STContent = pST(index)
End Property

Public Property Let STContent(ByVal index As Long, ByVal value As String)
    pST(index) = value
End Property

Private Sub Class_Initialize()
   ReDim pST(0 To 2)
End Sub

CODE RUN TO TEST:

Sub test()

   Dim foo As cPurchaseOrder
   Set foo = New cPurchaseOrder

   foo.STContent(0) = "test" '<--- Type mismatch here

   Debug.Print foo.STContent(0)

End Sub

Answer 1

Your getter would need to return a String() array for the types to be consistent:

Public Property Get ST() As String()

However I wouldn't recommend exposing an array like this. First because assigning typed arrays is rather painful, second because the setter (Property Let) is actually cheating here:

Public Property Let ST([ByRef] value() As String)

Unless you specify ByVal explicitly, a parameter is always passed ByRef in VBA... except there's this quirk about Property Let - the RHS/value parameter is always passed ByVal at run-time.

And arrays can only ever be passed ByRef.

Therefore, a property that gets (or assigns, actually) a whole array doesn't make much sense.

A better way would be to encapsulate the array (I'd make it a Variant though), and expose its contents (not the array itself) through an indexed property:

Private internal As Variant 'String array

'...

Public Property Get Content(ByVal index As Long) As String
    Content = internal(index)
End Property

Public Property Let Content(ByVal index As Long, ByVal value As String)
    internal(index) = value
End Property