public static void NavigateTo(string page)
        {
            if (!page.StartsWith("/"))
            {
                page = "/" + page;
            }

            RootVisual.Navigate(new Uri(page, UriKind.RelativeOrAbsolute));
        }
        private void OnNavigate(object param)
        {
            Uri uri = param as Uri;

            if (uri == null && param is string)
            {
                uri = new Uri((string)param, UriKind.Relative);
            }

            if (uri != null)
            {
                RootVisual.Navigate(uri);
            }
        }