title: Content convert to Frame in UWP with c++
body: <p>I have a problem when i try to convert Content Windows::UI::Xaml::Window::Current->Content  ---> Frame.
  in c#,i use this way like"Windows.UI.Xaml.Window.Current.Content as Frame".
  but in UWP with C++/CX.I cant find way.I want using Frame->Navigate(TypeName(xx)).</p>