title: Loop through all unbound controls on a form and clear data
body: <p>I would like to loop through all UNBOUND controls on my form and clear their data or reset their values.  I have textboxes, comboboxes and checkboxes.  Every time I try something like this:</p>
  
  <pre><code>Dim ctl As Control
      For Each ctl In Me.Controls
          If IsNull(ctl.ControlSource) Then
              ctl.Value = Nothing
          End If
      Next ctl
  </code></pre>
  
  <p>I get a runtime error saying:  </p>
  
  <blockquote>
    <p>438 This object doesn't support this property or method.</p>
  </blockquote>