title: Set a description field to be required if checkbox is checked "Yes" in an Access Form
body: <p>In my form I have a "Decline/Accept Contract" check box field and if this field is checked then I need the next field (long text) "Decline Reason" to be required. This field is only required is "Yes" is selected. I have tried variations of the following in the Before/AfterUpdate properties in both fields but nothing seems to work. </p>
  
  <p><code>If Me.Decline_Accept_Contract = "Yes" And IsNull(Me.Decline_Reason) Then
  MsgBox "Decline reason is required."
  Cancel = True
  Me.Decline_Reason.SetFocus
  End If</code></p>
  
  <p>I also tried setting a validation rule in the table properties
  <code>[Decline/Accept Reason]="Yes"</code> but this just gave me the validation message regardless of which field was clicked. It was not actually validating on the "yes" in the Decline/Accept Reason.</p>
  
  <p>Any help provided is appreciated. Thank you. </p>