public async Task Refresh()
{
var items = await ShoppingListService.GetShoppingListToShopItems();
ListItems = items.Select(i => new SelectableShoppingListItem(i)).ToList();
UnCheckedListItems = ListItems.Where(li => !li.Item.IsChecked).ToList();
CheckedListItems = ListItems.Where(li => li.Item.IsChecked).ToList();
StateHasChanged();
}