Order_Info GetOrder_InfoById(int orderID);
        List<Order_Info> GetOrder_Info(DateTime from, DateTime to);
        List<Order_Info> GetOrder_InfoByUser(int userID);

public interface IRepository<TEntity>
         where TEntity : class
    {
        /// <summary>
        /// 添加實體并提交到數據服務器
        /// </summary>
        /// <param name="item">Item to add to repository</param>
        void Add(TEntity item);

        /// <summary>
        /// 移除實體并(bing)提交(jiao)到數據(ju)服務器
        /// 如果(guo)表存在約束，需要先刪除子表信(xin)息
        /// </summary>
        /// <param name="item">Item to delete</param>
        void Remove(TEntity item);

        /// <summary>
        /// 修(xiu)改(gai)實體并提交到數(shu)據服務(wu)器
        /// </summary>
        /// <param name="item"></param>
        void Modify(TEntity item);

        /// <summary>
        /// 通過指定規約，得到實體對象(xiang)
        /// </summary>
        /// <param name="specification"></param>
        /// <returns></returns>
        TEntity GetEntity(ISpecification<TEntity> specification);

        /// <summary>
        /// 通(tong)用表(biao)達式樹，得到實體
        /// </summary>
        /// <param name="predicate"></param>
        /// <returns></returns>
        TEntity GetEntity(Expression<Func<TEntity, bool>> predicate);

        /// <summary>
        /// Get all elements of type {T} in repository
        /// </summary>
        /// <returns>List of selected elements</returns>
        IQueryable<TEntity> GetEntities();

        /// <summary>
        /// Get all elements of type {T} that matching a
        /// Specification <paramref name="specification"/>
        /// </summary>
        /// <param name="specification">Specification that result meet</param>
        /// <returns></returns>
        IQueryable<TEntity> GetEntities(ISpecification<TEntity> specification);

        /// <summary>
        /// 通用表(biao)達式樹,得到集合
        /// </summary>
        /// <param name="predicate"></param>
        /// <returns></returns>
        IQueryable<TEntity> GetEntities(Expression<Func<TEntity, bool>> predicate);
    }

 public interface IOrderRepository :
        Domain.Core.IRepository<Order_Info>
    {
        void InsertOrder(Order_Info entity);
    }

    /// <summary>
    /// 根(gen)據下單日期得(de)到訂單列表
    /// </summary>
    public class OrderFromDateSpecification : Specification<Order_Info>
    {
        DateTime? _fromDate;
        DateTime? _toDate;
        public OrderFromDateSpecification(DateTime? fromDate, DateTime? toDate)
        {
            _fromDate = fromDate ?? DateTime.MinValue;
            _toDate = toDate ?? DateTime.MaxValue;
        }
        public override global::System.Linq.Expressions.Expression<Func<Order_Info, bool>> SatisfiedBy()
        {
            Specification<Order_Info> spec = new TrueSpecification<Order_Info>();
            spec &= new DirectSpecification<Order_Info>(o => o.CreateDate >= _fromDate
                && o.CreateDate <= _toDate);
            return spec.SatisfiedBy();
        }
    }

    /// <summary>
    /// 通過用(yong)戶信息得到(dao)他(ta)的訂單(dan)列表
    /// </summary>
    public class OrderFromUserSpecification : Specification<Order_Info>
    {
        int _userID = default(Int32);
        public OrderFromUserSpecification(int userID)
        {
            _userID = userID;
        }
        public override global::System.Linq.Expressions.Expression<Func<Order_Info, bool>> SatisfiedBy()
        {
            Specification<Order_Info> spec = new TrueSpecification<Order_Info>();
            spec &= new DirectSpecification<Order_Info>(o => o.UserID == _userID);
            return spec.SatisfiedBy();
        }
    }

        /// <summary>
        /// 根據WEB層傳來及(ji)組(zu)件好的規約，返回集體
         /// </summary>
        /// <param name="spec"></param>
        /// <returns></returns>
        public List<Order_Info> GetOrder_InfoBySpec(ISpecification<Order_Info> spec)
        {
            return _iOrderRepository.GetEntities(spec).ToList();
        }

        public ActionResult List(int? userID)
        {
            ISpecification<Order_Info> spec = new OrderFromUserSpecification(userID ?? 0);
            var model = orderService.GetOrder_InfoBySpec(spec);
            return View(model);
        }