public NavigationQueue(NavigationManager parent)
{
_parent = parent;
_appViewModel = _parent._parent;
_rootFrame = _parent._rootFrame;
_rootFrame.Navigated += new NavigatedEventHandler(OnRootFrameNavigated);
_rootFrame.NavigationFailed += new NavigationFailedEventHandler(OnRootFrameNavigationFailed);
_rootFrame.NavigationStopped += new NavigationStoppedEventHandler(OnRootFrameNavigationStopped);
_appViewModel.MessageBoxManager.HasMessageBoxChanged += new EventHandler(OnHasMessageBoxChanged);
}