Create a validation rule for a control

1. Open a form in Design view.
   
   
2. Make sure the control is selected, and then click Properties on the toolbar to open the control's property sheet.
   
   
3. In the ValidationRule property box, type the validation rule; or, in a Microsoft Access database (.mdb), click the Build button to use the Expression Builder to create the validation rule.

   To see examples of validation rules, click .

4. In the ValidationText property box, type the error message that you want displayed if the text entered violates the validation rule.

Notes

• If you need more room to type in a property box, press SHIFT+F2 to open the Zoom box.
  
  
• In an Access database, if you set the ValidationRule property for the field in table Design view and also set the ValidationRule property for a control bound to that field, Microsoft Access enforces both rules — the control validation rule doesn't override the field validation rule.
  
  
• Access validates a field when you change data and try to leave the field, save the record, switch views, or close the form.