Question

If arrays are returned by reference, why doesn’t the following work:

'Class1 class module
Private v() As Double
Public Property Get Vec() As Double()
    Vec = v()
End Property
Private Sub Class_Initialize()
    ReDim v(0 To 3)
End Sub
' end class module

Sub Test1()
    Dim c As Class1
    Set c = New Class1
    Debug.Print c.Vec()(1) ' prints 0 as expected
    c.Vec()(1) = 5.6
    Debug.Print c.Vec()(1) ' still prints 0
End Sub

Answer 1

In VBA, arrays are never returned by reference unless they are returned through a ByRef parameter. Furthermore, whenever you use = to assign an array to a variable, you’ve made a new copy of the array, even if you’re assigning it to a ByRef argument inside of a procedure, so you’re pretty much out of luck trying to make this work.

Some alternative are…

• Use a VBA.Collection instead of an array.
• Make your own class that encapsulates an array and exposes procedures for indirectly accessing and manipulating the internal array.