Set the combo box's Limit to List property to Yes to allow the user to only
select a value that you permit.
If that's not the problem, you can put a command button on the form to Accept
the record, and lock it from further changes. This would have code like:
Private Sub cmdAccept_Click()
Dim strMsg As String
Dim iAns As Integer
strMsg = "Accettare questo disco e impedire che cambiare in futuro?"
iAns = MsgBox(strMsg, vbYesNo)
If iAns = vbNo Then
Exit Sub
Else
Me.Dirty = False ' write the record to disk
Me.comboboxname.Enabled = False
End If
End Sub
Then in the form's Current event, lock the combo box if a value was previously
selected for the field:
Private Sub Form_Current()
Me.Comboboxname.Enabled = IsNull(Me.Comboboxname)
End Sub
--
John W. Vinson [MVP]
Microsoft's replacements for these newsgroups:
http://social.msdn.microsoft.com/Forums/en-US/accessdev/
http://social.answers.microsoft.com/Forums/en-US/addbuz/
and see also
http://www.utteraccess.com