EF 真分页

    /// <summary>
    ///  真分页方法 
    /// </summary>
    /// <typeparam name="T">要查询得 类型</typeparam>
    /// <typeparam name="Tkey">要排序的类型</typeparam>
    public class TruePagingHelp<T, Tkey> where T : class
    {

        private testDbContext US_Context = new testDbContext();          /// DBContext 
　　　　　
        public TruePagingHelp(Expression<Func<T, Boolean>> searchCondition, Expression<Func<T, Tkey>> condition, Boolean desc, int PageIndex, int pageSize)
        {
            Int32 count = 0;
            PageIndex = PageIndex <= 0 ? 1 : PageIndex;
            this.PageIndex = PageIndex; /// 第几页
            this.PageSize = pageSize; /// 每页数据量
            this.DataSource = this.GetData<T, Tkey>(searchCondition, condition, desc, PageIndex, pageSize, out count);
            this.PageCount = (int)Math.Ceiling(count / (Double)pageSize);  /// 总共页数
        }

        /// <summary>
        /// 分页源数据
        /// </summary>
        public IEnumerable<T> DataSource { get; private set; }
        /// <summary>
        /// 每页记录数量
        /// </summary>
        public int PageSize { get; private set; }
        /// <summary>
        /// 当前页数
        /// </summary>
        public int PageIndex { get; set; }

        //分页总数
        public int PageCount { get; private set; }

        public IEnumerable<T> GetData<T, Tkey>(Expression<Func<T, Boolean>> filterCondition, Expression<Func<T, Tkey>> sortCondition, Boolean desc, int PageIndex, int pageSize, out int total) where T : class
        {
            IEnumerable<T> list;
            total = US_Context.Set<T>().Where<T>(filterCondition).Count();
            if (desc)
            {
                list = US_Context.Set<T>().Where<T>(filterCondition).OrderByDescending(sortCondition).Skip(pageSize * (PageIndex - 1)).Take(pageSize).ToList();

            }
            else
            {
                list = US_Context.Set<T>().Where<T>(filterCondition).OrderBy(sortCondition).Skip(pageSize * (PageIndex - 1)).Take(pageSize).ToList();
            }
            return list;
        }
    }

 其中使用了， 泛型、泛型约束等；

写了EF 真分页 会EF查询效率有很了解，值得自己去写；