Dim aCTRL as control
 
For Each aCTRL in me.Controls
   If TypeName(aCTRL) = "TextBox" and len(trim(aCTRL.text)) = 0 then
      msgbox "Jetzt müssten Sie was eingeben".
   Else
      'Entweder isses keine TextBox, oer es steht was drin
   EndIf
Next