Loop through form header for controls null values

[SamT]

I don't usually do Access, but something like this

Dim Ctrl As Object
Dim MissingValues as boolean

For Each Ctrl in Me.Controls
   If Ctrl.ControlType = acTextBox then
     If Ctrl.Value = "" Then
        MissingValues = True
        Exit For
     End IF
   ElseIf Ctrl.ControlType = acListtBox then
     If Ctrl.Value = "" Then
        MissingValues = True
        Exit For
     End IF
   End if
Next

If MissingValues Then 
   Show message
Else
   Show buttons