protected void btnNewProductSpecification_Click(object sender, EventArgs e)
        {
            try
            {
                Product product = ProductManager.GetProductById(this.ProductId);
                if (product != null)
                {
                    if (String.IsNullOrEmpty(ddlNewProductSpecificationAttribute.SelectedValue))
                    {
                        throw new NopException("Please select specification attribute");
                    }
                    if (String.IsNullOrEmpty(ddlNewProductSpecificationAttributeOption.SelectedValue))
                    {
                        throw new NopException("Please select specification attribute option");
                    }

                    int  specificationAttributeId = int.Parse(ddlNewProductSpecificationAttribute.SelectedItem.Value);
                    int  productSpecificationAttributeOptionId = Convert.ToInt32(ddlNewProductSpecificationAttributeOption.SelectedValue);
                    bool allowFiltering    = chkNewAllowFiltering.Checked;
                    bool showOnProductPage = chkNewShowOnProductPage.Checked;
                    int  productSpecificationAttributeDisplayOrder = txtNewProductSpecificationAttributeDisplayOrder.Value;

                    ProductSpecificationAttribute productSpecificationAttribute = SpecificationAttributeManager.InsertProductSpecificationAttribute(
                        product.ProductId,
                        productSpecificationAttributeOptionId,
                        allowFiltering,
                        showOnProductPage,
                        productSpecificationAttributeDisplayOrder);

                    BindData();
                }
            }
            catch (Exception exc)
            {
                processAjaxError(exc);
            }
        }