public void AddOnlineBook(CustomerOnlineBook customerOnlineBook)
{
if (isOnlineBookExistsInCustomerList(customerOnlineBook) == true)
{
Console.WriteLine("Online book is already exists in customer list");
}
else
{
using (var newDal = new DBdal())
{
newDal.customerOnlineBooks.Add(customerOnlineBook);
newDal.SaveChanges();
}
}
}
