private void btnAñadir_ChangeIndex(object sender, Gabriel.Cat.Uwp.ToggleButtonArgs e)
 {
     ItemCronos newItem = new ItemCronos();
     newItem.OpenHistory += OpenHistoryEvent;
     items.Add(newItem.Item);
     itemsControls.Add(newItem);
     stkTiempos.Children.Add(newItem);
     ActualizaBackGroundItems();
 }
        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            List<itemCronos> todosLosItems =e.Parameter as List<itemCronos>;
            ItemCronos item;
            base.OnNavigatedTo(e);
            if (todosLosItems != null)
            {
                items = todosLosItems;//restauro los items que tenia
                for (int i = 0; i < todosLosItems.Count; i++)
                {

                    item = new ItemCronos(todosLosItems[i]);
                    itemsControls.Add(item);
                    stkTiempos.Children.Add(item);
                    item.OpenHistory += OpenHistoryEvent;
                    item.EstaEncendido = todosLosItems[i].EstaOn;
                }
                ActualizaBackGroundItems();
            }
            else if (!EstaCargado) LoadXml();

        }