title: 'System.Web.HttpContextBase' does not contain a definition for 'GetOwinContext'
body: <pre><code>private IAuthenticationManager AuthenticationManager
  {
      get
      {
          return HttpContext.GetOwinContext().Authentication;
      }
  }
  </code></pre>
  
  <p>I get the error :   </p>
  
  <blockquote>
    <p>'System.Web.HttpContextBase' does not contain a definition for
    'GetOwinContext' and no extension method 'GetOwinContext' accepting a
    first argument of type 'System.Web.HttpContextBase' could be found
    (are you missing a using directive or an assembly reference?)</p>
  </blockquote>
  
  <p>What might be wrong?   </p>