title: Stop a WPF Textbox from losing focus
body: <p>I have a WPF <code>Textbox</code>, that I want to check that the text value is correct before I allow it to lose keyboard/focus.</p>
  
  <p>I have tried setting e.Handled in the <code>InputBox_LostFocus</code> &amp; <code>InputBox_LostKeyboardFocus</code> events, but it doesnt seem to be achieving what I want.</p>
  
  <p>Any suggestions on how I can lock focus to a <code>Textbox</code>?</p>