protected override void WndProc(ref Message msg) in wpf

Question

I am uing the following in WinForms. How do I use it in WPF? 

 

protected override void WndProc(ref Message msg)

{

   unsafe

   {

      if (msg.Msg == 123)

      {

            ...... 

      }

   } 

   base.WndProc(ref msg);

}