protected void btnOrder_Click(object sender, EventArgs e) { string str_productId = txtProductID.Text; string str_quantity = txtQuantity.Text; // Dari session di cast ke User terus diambil Id nya int userId = ((User)Session["user"]).Id; string response = CartController.CheckInsert(userId, str_productId, str_quantity); if (response == "") { lblError.Text = ""; FillGrid(); } else { lblError.Text = response; } }