/// <summary>
/// Gets a value indicating whether all <c>CartItem</c> in the <c>IEnumerable<CartItem></c> are email <c>GiftCard</c>
/// </summary>
public static bool IsAllEmailGiftCards(this IEnumerable <CartItem> cartItems)
{
return(cartItems
.All(ci => GiftCard.ProductIsEmailGiftCard(ci.ProductID)));
}
static public bool IsAllFreeShippingComponents(IEnumerable <CartItem> cartItems)
{
return(cartItems
.All(ci => ci.FreeShipping || !ci.Shippable || ci.IsDownload || GiftCard.ProductIsEmailGiftCard(ci.ProductID)));
}