private void lstMenuItems_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (lbiLogOff.IsSelected)
            {
                MyLocalStorage.RemoveFromLocalStorage(@"usuario");
                Frame.Navigate(typeof(MainPage));
            }
            else if (!lbiLogOff.IsSelected && !lbiHome.IsSelected)
            {
                btnBack.Visibility = Visibility.Visible;

                if (lbiTarefas.IsSelected)
                {
                    frmConteudo.Navigate(typeof(NovaTarefaPage));
                }
            }
            else
            {
                btnBack.Visibility = Visibility.Collapsed;
                frmConteudo.Navigate(typeof(TarefasPage));
            }
        }