public void GenerateItems()
    {
        // _c1Items.ForEach(i => i.Category = Category.C1);
        // _c2Items.ForEach(i => i.Category = Category.C2);
        // _c3Items.ForEach(i => i.Category = Category.C3);
        // _c4Items.ForEach(i => i.Category = Category.C4);
        // _c5Items.ForEach(i => i.Category = Category.C5);
        // _c6Items.ForEach(i => i.Category = Category.C6);
        // _c7Items.ForEach(i => i.Category = Category.C7);
        // _c8Items.ForEach(i => i.Category = Category.C8);

        _allItems.AddRange(_c1Items);
        _allItems.AddRange(_c2Items);
        _allItems.AddRange(_c3Items);
        _allItems.AddRange(_c4Items);
        _allItems.AddRange(_c5Items);
        _allItems.AddRange(_c6Items);
        _allItems.AddRange(_c7Items);
        _allItems.AddRange(_c8Items);


        CategoryController[] allCategoryControllers =
            FindObjectsOfType <CategoryController>().ToArray();
        for (int i = 0; i < Enum.GetNames(typeof(Category)).Length; i++)
        {
            Category           category      = (Category)i;
            IEnumerable <Item> categoryItems = _allItems.Where(it => it.Category == category);
            foreach (CategoryController categoryObj in allCategoryControllers.Where(c => c.category == category))
            {
                CategoryPanelController categoryPanel = categoryObj.CategoryPanel;
                // if (categoryPanel.items == null)
                //     categoryPanel.items = new List<Item>();
                foreach (Item item in categoryItems)
                {
                    categoryPanel.AddItem(item);
                }
                //categoryPanel.items.AddRange(categoryItems);
                categoryPanel.GenerateItems();
            }
        }
    }