title: Depopulating combo box when selecting a different item
body: <p>I'm having trouble clearing a combo box without the use of a button. </p>
  
  <p>I'm attempting to populate a drop down combo box dependent upon which item a user selects. I.E if user clicks North East, another combo box gives the options to select New York or Massachusetts.</p>
  
  <p>My problem occurs when selecting a different option in a combo box that has already had an event occur. For example if the user wants to go back and click South East instead of North East, instead of clearing the previous options the combo box just populates adds the new cities to the combo box.</p>
  
  <p>I can't figure out how to clear the previous ones without using a clear button, but using one is not an option.</p>
  
  <pre><code>    If comboRegionBox.SelectedIndex &lt;&gt; -1 Then
          strRegion = comboRegionBox.Items(comboRegionBox.SelectedIndex)
          txtBoxRegion.Text = strRegion
      End If
  
      If comboRegionBox.SelectedIndex = 0 Then
          With comboStateBox.Items
              .Add("New York")
              .Add("Massachusetts")
          End With
      End If
  
      If comboStateBox.SelectedIndex &lt;&gt; -1 Then
          strState = comboStateBox.Items(comboStateBox.SelectedIndex)
          txtBoxState.Text = strState
      End If
  
      If comboStateBox.SelectedIndex = 0 Then
          With comboCityBox.Items
              .Add("New York City")
              .Add("Rochester")
          End With
      End If
  
      If comboStateBox.SelectedIndex = 1 Then
          With comboCityBox.Items
              .Add("Boston")
              .Add("Concord")
          End With
      End If
  </code></pre>