asp.net 7.分页

分页

SQL:

select * from(
  select *,row_number()over(order by id) as num from T_userInfo) as t
  where t.num >=1 and t.num <=4

数据层(UserInfoDal):

        /// <summary>
        /// 根据指定的范围，获取指定的数据
        /// </summary>
        /// <param name="start"></param>
        /// <param name="end"></param>
        /// <returns></returns>
        public List<UserInfo> GetPageList(int start,int end)
        {
            string sql = "select * from(select *,row_number()over(order by id) as num from UserInfo) as t where t.num>=@start and t.num<=@end";
            SqlParameter[] pars = { 
                                  new SqlParameter("@start",SqlDbType.Int),
                                  new SqlParameter("@end",SqlDbType.Int)
                                  };
            pars[0].Value = start;
            pars[1].Value = end;
            DataTable da=SqlHelper.GetDataTable(sql, CommandType.Text, pars);
            List<UserInfo> list = null;
            if (da.Rows.Count > 0)
            {
                list = new List<UserInfo>();
                UserInfo userInfo = null;
                foreach (DataRow row in da.Rows)
                {
                    userInfo = new UserInfo();
                    LoadEntity(userInfo, row);
                    list.Add(userInfo);
                }
            }
            return list;
        }

        /// <summary>
        /// 获取总的记录数
        /// </summary>
        /// <returns></returns>
        public int GetRecordCount()
        {
            string sql = "select count(*) from UserInfo";
           return Convert.ToInt32(SqlHelper.ExecuteScalar(sql,CommandType.Text));
        }

业务层(UserInfoService):

       /// <summary>
       /// 计算获取数据的访问，完成分页
       /// </summary>
       /// <param name="pageIndex">当前页码</param>
       /// <param name="pageSize">每页显示的记录数据</param>
       /// <returns></returns>
       public List<UserInfo> GetPageList(int pageIndex,int pageSize)
       {
           int start=(pageIndex-1)*pageSize+1;
           int end = pageIndex * pageSize;
          return UserInfoDal.GetPageList(start, end);

       }
       /// <summary>
       /// 获取总的页数
       /// </summary>
       /// <param name="pageSize">每页显示的记录数</param>
       /// <returns></returns>
       public int GetPageCount(int pageSize)
       {
           int recoredCount = UserInfoDal.GetRecordCount();//获取总的记录数.
           int pageCount =Convert.ToInt32(Math.Ceiling((double)recoredCount / pageSize));
           return pageCount;
       }

SqlHelper 添加ExecuteScalar方法(返回第一行第一列):

 public static object ExecuteScalar(string sql, CommandType type, params SqlParameter[] pars)
       {
           using (SqlConnection conn = new SqlConnection(connStr))
           {
               using (SqlCommand cmd = new SqlCommand(sql, conn))
               {
                   if (pars != null)
                   {
                       cmd.Parameters.AddRange(pars);
                   }
                   cmd.CommandType = type;
                   conn.Open();
                   return cmd.ExecuteScalar();
               }
           }
       }

UI层(首页/前页/下页/尾页):

<a href="NewList.aspx?pageIndex=1">首页</a>  |  
<a href="NewList.aspx?pageIndex=<%=PageIndex-1<1?1:PageIndex-1%>"> 前页</a>  |  
<a href="NewList.aspx?pageIndex=<%=PageIndex+1>PageCount?PageCount:PageIndex+1%>">后页</a> | 
<a href="NewList.aspx?pageIndex=<%=PageCount%>"> 尾页 </a>        页次：<%=PageIndex%>/<%=PageCount%>页 

using CZBK.ItcastProject.Model;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace CZBK.ItcastProject.WebApp._2015_5_30
{
    public partial class NewList : System.Web.UI.Page
    {
        public string StrHtml { get; set; }
        public int PageIndex { get; set; }
        public int PageCount { get; set; }
        protected void Page_Load(object sender, EventArgs e)
        {
            int pageSize=5;
            int pageIndex;
            if(!int.TryParse(Request.QueryString["pageIndex"],out pageIndex))
            {
                pageIndex=1;
            }
            BLL.UserInfoService UserInfoService = new BLL.UserInfoService();
            int pagecount = UserInfoService.GetPageCount(pageSize);//获取总页数
            PageCount = pagecount;
            //对当前页码值范围进行判断
            pageIndex = pageIndex < 1 ? 1 : pageIndex;
            pageIndex = pageIndex > pagecount ? pagecount : pageIndex;
            PageIndex = pageIndex;
            List<UserInfo>list= UserInfoService.GetPageList(pageIndex,pageSize);//获取分页数据
            StringBuilder sb = new StringBuilder();
            foreach (UserInfo userInfo in list)
            {
               sb.AppendFormat("<li><span>{0}</span><a href='#' target='_blank'>{1}</a></li>",userInfo.RegTime.ToShortDateString(),userInfo.UserName);
            }
            StrHtml = sb.ToString();
        }
    }
}