void OnAddItemClicked(object sender, EventArgs e)
        {
            var OnlineProduct = new OnlineProduct();
            //var OnlineProduct = new OnlineProduct () {
            //	Id = Guid.NewGuid ().ToString ()
            //};
            var todoPage = new OnlineProductPage(true);

            todoPage.BindingContext = OnlineProduct;
            Navigation.PushAsync(todoPage);
        }
        void OnItemSelected(object sender, SelectedItemChangedEventArgs e)
        {
            TodoREST.OnlineProduct OnlineProduct = (TodoREST.OnlineProduct)e.SelectedItem;
            OnlineProduct.Init(OnlineProduct);
            var todoPage = new OnlineProductPage();

            if (OnlineProduct.UpdatedDate == null)
            {
                todoPage._updatedDate = DateTime.Now;
            }
            else
            {
                todoPage._updatedDate = OnlineProduct.UpdatedDate.Value;
            }
            //OnlineProduct.ImageUrl =Constants.Image + OnlineProduct.Id + ".jpg";
            todoPage.BindingContext = OnlineProduct;

            Navigation.PushAsync(todoPage);
        }