John
edtControl..State = Grayed defeats everything but may not be the look you are after.
If you opt for edtControl..State = DisplayOnly, possible with the Brushcolor set to light gray, then make sure you have unchecked the Automatic Erase and With Selection on the Details tab of the edit control.
If you do not then the user can still access and change the content.
Of course it will not be updated in the DB but it can lead to all sorts of confusion.
Regards
DerekT