RaiseEvent

 
'Class1.cls
Event Changing(ByVal OldValue As String, ByVal NewValue As String)
 
Private Value_ As String
 
Property Get Value As String
    Value = Value_
End Property
 
Property Let Value(ByVal NewValue As String)
    RaiseEvent Changing(Value_, NewValue)
    Value_ = NewValue
End Property
 
'Macro.bas
'#Uses "Class1.cls"
 
Dim WithEvents c1 As Class1
 
Sub Main
    Set c1 = New Class1
    c1.Value = "Hello"
    c1.Value = "Goodbye"
End Sub
 
Sub c1_Changing(ByVal OldValue As String, ByVal NewValue As String)
    Debug.Print "OldValue=""" & OldValue & """, NewValue=""" & NewValue & """"
End Sub