title: Impersonate a Active Directory user in MVC application with Windows Authentication
body: <p>I am building an admin module for an intranet MVC application. This application implements Windows Authentication (users are automatically logged in).</p>
  
  <p>Currently I base all the user experience based around their HttpContext.User.Identity data.</p>
  
  <p>What I need to do is to be able to impersonate an user so I can replicate their experience if they are having problems.</p>
  
  <p>With Forms Authentication this is very straight forward...</p>
  
  <p>I tried replacing the IPrincipal.User object in the HttpContext but this only has a getter not a setter.</p>
  
  <p>any pointers would be greatly appreciated.</p>
  
  <p>Thanks.</p>