protected void Page_Load(object sender, EventArgs e)
        {
            shopController sc    = new shopController();
            string         title = (string)Session["booktitle"];
            //string title = "The Hate U Give";//For testing purpose
            Book     b = sc.loadBook(title);
            Category c = sc.loadCategory(b);//Mr. Derek, I feel it is not necessary to have a seperate table for category......

            txtTitle.Text    = b.Title;
            txtISBN.Text     = b.ISBN;
            txtAuthor.Text   = b.Author;
            txtCat.Text      = c.Name;
            txtQuantity.Text = b.Stock.ToString();
            txtPrice.Text    = b.Price.ToString();//Original Price
            Image1.ImageUrl  = "~/images/" + b.ISBN + ".jpg";
        }
        protected void btnAddToCart_Click(object sender, EventArgs e)
        {
            shopController sc    = new shopController();
            string         title = (string)Session["booktitle"];
            Book           b     = sc.loadBook(title);

            //For Luke's login part
            //if (Session["username"] == null)
            //{
            //    Response.Redirect("Login.aspx");
            //}

            if (Session["cart"] != null)
            {
                CartList cl = (CartList)Session["cart"];

                int     id    = b.BookID;
                decimal price = 0;
                price = b.Price;

                cartController cc = new cartController();
                cl = cc.addItem(cl, id, title, price);
                Session["cart"] = cl;
            }
            else
            {
                CartList cl = new CartList();

                int     id    = b.BookID;
                decimal price = 0;
                price = b.Price;

                cartController cc = new cartController();
                cl = cc.addItem(cl, id, title, price);
                Session["cart"] = cl;
            }
            Response.Redirect("ViewCart.aspx");
        }