Abp.Linq.Extensions扩展(1)--static class QueryableExtensions

　　// 摘要:
        //     Used for paging with an Abp.Application.Services.Dto.IPagedResultRequest object.
        //
        // 参数:
        //   query:
        //     Queryable to apply paging
        //
        //   pagedResultRequest:
        //     An object implements Abp.Application.Services.Dto.IPagedResultRequest interface
        public static IQueryable<T> PageBy<T>(this IQueryable<T> query, IPagedResultRequest pagedResultRequest);

　　 // 摘要:
        //     Used for paging. Can be used as an alternative to Skip(...).Take(...) chaining.
        public static IQueryable<T> PageBy<T>(this IQueryable<T> query, int skipCount, int maxResultCount);

　　// 摘要:
        //     Filters a System.Linq.IQueryable`1 by given predicate if given condition is true.
        //    当给定的条件为True 的时候,通过给定的委托条件来查询
        // 参数:
        //   query:
        //     Queryable to apply filtering
        //
        //   condition:
        //     A boolean value
        //
        //   predicate:
        //     Predicate to filter the query
        //
        // 返回结果:
        //     Filtered or not filtered query based on condition
        public static IQueryable<T> WhereIf<T>(this IQueryable<T> query, bool condition, Expression<Func<T, bool>> predicate);

　　// 摘要:
        //     Filters a System.Linq.IQueryable`1 by given predicate if given condition is true.
        //
        // 参数:
        //   query:
        //     Queryable to apply filtering
        //
        //   condition:
        //     A boolean value
        //
        //   predicate:
        //     Predicate to filter the query
        //
        // 返回结果:
        //     Filtered or not filtered query based on condition
        public static IQueryable<T> WhereIf<T>(this IQueryable<T> query, bool condition, Expression<Func<T, int, bool>> predicate);