title: How do I "Cancel an event"?
body: <p>I have two DateTimePickers <em>dtpDateFrom</em> and <em>dtpDateTo</em>.</p>
  
  <p>I already coded a conditional statement that if dtpDateTo is earlier than dtpDateFrom via their <em>ValueChanged</em> event, I would get an error message, but it still <strong>applies the change.</strong></p>
  
  <p>Example:</p>
  
  <ol>
  <li>dtpDateFrom = July 2</li>
  <li>dtpDateTo = July 3</li>
  <li>If I change <em>dtpDateFrom</em> to July 4 ~> error message + <strong>without performing the July 4 change</strong></li>
  </ol>