public Item(UserData u, string i)
{
InitializeComponent();
this.user = u;
this.isbn = i;
bookItem = new BookCatalog();
bookCart = new BookCart();
dsBookItem = bookItem.load_Item(isbn);
this.DataContext = dsBookItem.Tables["Item"];
cart_val.Text = "" + bookCart.cartItems(user.UserID);
}