MVC分頁控件之二，為IQueryable定義一個擴充方法，直接反回PagedList<T>結果集

namespace Entity

{

    public interface IPagedList

    {

        /// <summary>

        /// 記錄數

        /// </summary>

        int TotalCount { get; set; }

        /// 頁數

        int TotalPages { get; set; }

        /// 目前頁

        int PageIndex { get; set; }

        /// 頁面大小

        int PageSize { get; set; }

        /// 是否上一頁

        bool IsPreviousPage { get; }

        /// 是否下一頁

        bool IsNextPage { get; }

    }

    /// <summary>

    /// 分頁通用類

    /// </summary>

    /// <typeparam name="T"></typeparam>

    public class PagedList<T> : List<T>, IPagedList

        /// 資料源為IQueryable的範型

        /// <param name="source">資料源</param>

        /// <param name="index">目前頁</param>

        /// <param name="pageSize">每頁顯示多少條記錄</param>

        public PagedList(IQueryable<T> source, int index, int pageSize)

        {

            if (source != null) //判斷傳過來的實體集是否為空

            {

                int total = source.Count();

                this.TotalCount = total;

                this.TotalPages = total / pageSize;

                if (total % pageSize > 0)

                    TotalPages++;

                this.PageSize = pageSize;

                if (index > this.TotalPages)

                {

                    index = this.TotalPages;

                }

                if (index < 1)

                    index = 1;

                this.PageIndex = index;

                this.AddRange(source.Skip((index - 1) * pageSize).Take(pageSize).ToList()); //Skip是跳到第幾頁，Take傳回多少條

            }

        }

        /// 總頁數

        public int TotalPages { get; set; }

        /// 總記錄數

        public int TotalCount { get; set; }

        public int PageIndex { get; set; }

        /// 每頁顯示多少條記錄

        public int PageSize { get; set; }

        /// 是否有上一頁

        public bool IsPreviousPage { get { return (PageIndex > 0); } }

        /// 是否有下一頁

        public bool IsNextPage { get { return (PageIndex * PageSize) <= TotalCount; } }

        private NameValueCollection _AddParameters = new NameValueCollection();

        /// 分頁參數

        public NameValueCollection AddParameters

            get { return _AddParameters; }

            set { _AddParameters = value; }

    /// PagedList擴充類

    public static class ExtendPagedList

        ///  傳回PagedList<T>類型的IQueryable的擴充方法

        /// <typeparam name="T"></typeparam>

        /// <param name="linq"></param>

        /// <param name="pageIndex"></param>

        /// <param name="pageSize"></param>

        /// <returns></returns>

        public static PagedList<T> ToPagedList<T>(this IQueryable<T> linq, int pageIndex, int pageSize)

            return new PagedList<T>(linq, pageIndex, pageSize);

}