public async Task <IActionResult> OnPostFilteredProductsAsync(string productName, int pageNumber)
        {
            if (!string.IsNullOrEmpty(productName))
            {
                ProductList = await _productApi.GetFilteredProducts(productName);
            }
            else
            {
                ProductList = await _productApi.GetProductByPage(pageNumber);
            }

            CategoryList = ProductList.Select(p => p.Category).Distinct();
            return(Page());
        }