/// <summary>
        /// 动态查询
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="queryable"></param>
        /// <param name="query"></param>
        /// <returns></returns>
        public static IQueryable <T> DynamicQuery <T>(this IQueryable <T> queryable, QueryCondition query)
        {
            if (queryable == null)
            {
                throw new ArgumentNullException(nameof(queryable));
            }

            if (query == null)
            {
                return(queryable);
            }

            return(ExpressionExpand <T> .DynamicQuery(queryable, query));
        }
        /// <summary>
        /// 动态排序
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="queryable"></param>
        /// <param name="sortings"></param>
        /// <returns></returns>
        public static IQueryable <T> DynamicSort <T>(this IQueryable <T> queryable, IEnumerable <SortingParameter> sortings)
        {
            if (queryable == null)
            {
                throw new ArgumentNullException(nameof(queryable));
            }

            if (sortings == null || !sortings.Any())
            {
                return(queryable);
            }


            return(ExpressionExpand <T> .DynamicSort(queryable, sortings));
        }
 /// <summary>
 /// 条件:与
 /// </summary>
 /// <typeparam name="T"></typeparam>
 /// <param name="this"></param>
 /// <param name="expression"></param>
 /// <returns></returns>
 public static Expression <Func <T, bool> > And <T>(this Expression <Func <T, bool> > @this, Expression <Func <T, bool> > expression)
 {
     return(ExpressionExpand <T> .And(@this, expression));
 }
 /// <summary>
 /// 获取条件表达式
 /// </summary>
 /// <typeparam name="T"></typeparam>
 /// <returns></returns>
 public static Expression <Func <T, bool> > GetExpression <T>()
 {
     return(ExpressionExpand <T> .GetExpression());
 }