title: Route an event into sibling control in WPF
body: <p>I have a TextBox control for search, and a TreeView control below it. What I need is when I press the "Down Key ↓" <strong>while the focus on the search TextBox</strong>, I need to tell the TreeView "<strong>a Down Key has been pressed while the focus on you</strong>" ... I don't need to raise a KeyUp event on the TreeView or something, I need it to do the same action as if I pressed the Down Key while the focus on it!</p>
  
  <p>Is this possible?</p>