public List <T> GetAll()
 {
     using (ShoppingMallEntities context = new ShoppingMallEntities())
     {
         return(context.Set <T>().ToList());
     }
 }
 public List <S> Select <S>(Expression <Func <T, S> > selector)
 {
     using (ShoppingMallEntities context = new ShoppingMallEntities())
     {
         return(context.Set <T>().Select(selector).ToList());
     }
 }
        public void Insert(T entity)
        {
            using (ShoppingMallEntities context = new ShoppingMallEntities())
            {
                context.Set <T>().Add(entity);

                context.SaveChanges();
            }
        }