Private tmpVar As String
Private VarIsSetting As Boolean
 
Public Event VarCheck()
 
Public Property Get CheckVar() As String
   CheckVar = tmpVar
End Property
 
Public Property Let CheckVar(nVar As String)
    If Not VarIsSetting Then
       VarIsSetting = True
       Exit Property
    End If
 
    If nVar <> tmpVar Then
       RaiseEvent VarCheck
    End IF
 
    tmpVar = nVar
End Property

Private WithEvents myVar As VarCheck
 
Private Sub Command1_Click()
   myVar.CheckVar = "Test2"
End Sub
 
Private Sub Form_Load()
   Set myVar = New VarCheck
   myVar.CheckVar = "Test"
End Sub
 
Private Sub myVar_VarCheck()
   MsgBox "uppsss .... geändert :-("
End Sub