/// <summary>
 /// 添加排序
 /// </summary>
 /// <param name="p"></param>
 public void SetOrders(PredicateOrder <T> p)
 {
     if (_orderDict == null)
     {
         _orderDict = new List <PredicateOrder <T> >();
     }
     _orderDict.Add(p);
 }
        public void SetOrder(string Field, string Sort)
        {
            PredicateOrder <T> po;

            if (Sort.ToLower().Trim() == "desc")
            {
                po = new PredicateOrder <T>(Field, OrderType.DESC);
            }
            else
            {
                po = new PredicateOrder <T>(Field, OrderType.ASC);
            }
            this.SetOrders(po);
        }