public bool SetDefault(int userId, int id)
        {
            if (id <= 0 || userId <= 0)
            {
                return(false);
            }

            using (var cxt = DbContext(DbOperation.Write))
            {
                cxt.BeginTransaction();

                var repo = new UserAddressRepo(cxt);
                var flag = repo.SetDefault(userId, id);

                if (flag)
                {
                    cxt.Commit();
                }
                else
                {
                    cxt.Rollback();
                }

                return(flag);
            }
        }
        public UserAddressDto GetDefault(int userId)
        {
            if (userId <= 0)
            {
                return(null);
            }

            using (var cxt = DbContext(DbOperation.Read))
            {
                var repo = new UserAddressRepo(cxt);
                return(repo.GetDefault(userId));
            }
        }
        public IEnumerable <UserAddressDto> List(int userId)
        {
            if (userId <= 0)
            {
                return(null);
            }

            using (var cxt = DbContext(DbOperation.Read))
            {
                var repo = new UserAddressRepo(cxt);
                return(repo.List(userId));
            }
        }