function checkValues(frm as Form) as boolean
Dim ctl As Control
 
   For Each ctl In frm.Controls
      If TypeOf ctl Is CommandButton Then
         'mach irgendwas mit dem control
      ElseIf TypeOf ctl Is TextBox then
         if ctl.text = "" then exit function
      ElseIf TypeOf ctl Is ComboBox Or _
             TypeOf ctl Is ListBox Then
               'mach irgendwas
      End If
    Next
    checkValues = true
end function
 
'Aufruf in deiner form z.b. hinter einem speichern button
if not checkValues(me) then
   msgbox "Sie haben nicht alle textboxen ausgefüllt", vbinformation
   exit sub
end if