重学>ASP.NET小实例>DataReader手工分页

花了两天时间，参考别人写好，

首先表数据如下：

 

直接上代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public partial class learnFenye : System.Web.UI.Page
{
    SqlConnection sqlconn;
    protected void Page_Load(object sender, EventArgs e)
    {
        int PageSize = 3;//每页显示条数
        int PageCount = 0;//总共页数
        int RecordCount = 0;//数据库记录条数
        int CurrentPage = 0;//当前页数

        


        string conn = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;
        sqlconn = new SqlConnection(conn);
        sqlconn.Open();
        //第一步：首先计算数据库的记录条数
        //RecordCount=
        RecordCount = CountRecord();
        Response.Write("数据库的记录条数有：" + RecordCount + "<br />");

        //第二步: 计算页数
        PageCount = RecordCount / PageSize;
        if (RecordCount % PageSize > 0)//如果整除不了，要多出一页
        {
            PageCount = PageCount + 1;
        }
        Response.Write("分页的页数有：" + PageCount + "<br />");


        //第三步：获取当前页数
        if (Request.QueryString["page"] != null)
        {
            CurrentPage = Convert.ToInt32(Request.QueryString["page"]);
        }
        else
        {
            CurrentPage = 1;//如果没设置，就从第一页开始
        }
        Response.Write("当前页数是：" + CurrentPage + "<br />");


        //第四步： 开始分页
        string sql = "SELECT TOP (" + PageSize + ") TicketAutoId, value FROM Ticket ";
        sql += "where TicketAutoId not in (select top " + (CurrentPage - 1) * PageSize + " TicketAutoId from Ticket order by TicketAutoId ) ";
        sql += " ORDER BY TicketAutoId";
        SqlCommand sqlcmd = new SqlCommand(sql, sqlconn);
        SqlDataReader sqldr = sqlcmd.ExecuteReader();
        string HTMLTable;
        HTMLTable = "<table>";
        while(sqldr.Read())
        {
            
            HTMLTable += "<tr><td>"+sqldr.GetInt32(0).ToString()+"</td></tr>";   
            //Response.Write(sqldr.GetInt32(0));
        }
        HTMLTable += "</table>";
        Response.Write(HTMLTable);
        //sqldr.Close();

        //第五步：设置首页，上一页，下一页，末页按钮
        int pagePre, pageNext;
        pagePre = CurrentPage - 1;
        pageNext = CurrentPage + 1;
        string pageHtml;

        if (pagePre == 0)
        {
            pageHtml = "首页&nbsp;上页";
        }
        else
        {
            pageHtml = "<a href='learnfenye.aspx?page=1'>首页</a>&nbsp;<a href='learnfenye.aspx?page=" + pagePre + "'>上页</a>";
        }

        if (pageNext > PageCount)
        {
            pageHtml += "&nbsp;下页&nbsp;末页";
        }
        else
        {
            pageHtml += "&nbsp;<a href='learnfenye.aspx?page=" + pageNext + "'>下页</a>";
            pageHtml += "&nbsp;<a href='learnfenye.aspx?page=" + PageCount + "'>末页</a>";
        }
        IndexButton.InnerHtml = pageHtml;

    }

    private int CountRecord()//统计数据库表的记录条数
    {
        int count = 0;
        string sql = "select count(*) from Ticket";
        SqlCommand sqlcmd = new SqlCommand(sql, sqlconn);
        SqlDataReader sqldr = sqlcmd.ExecuteReader();
        if (sqldr.Read() != null)
        {
            count = sqldr.GetInt32(0);
        }
        sqldr.Close();
        return count;
    }
}

 改进的地方：第三步获取当前页，要判断当前页是否合法。

//第三部：获取当前页数
            if (Request.QueryString["page"] != null)
            {
                int dangqianyeshu = 1;
                try
                {
                    dangqianyeshu = Convert.ToInt32(Request.QueryString["page"]);
                    if (dangqianyeshu > PageCount)
                    {
                        Response.Write("超过最大页");
                        Response.End();
                    }
                }
                catch (Exception ex)
                {
                    Response.Write("页数非法！");
                }
                finally
                {
                    CurrentPage = Convert.ToInt32(dangqianyeshu);
                }
            }
            else
            {
                CurrentPage = 1;
            }
            Response.Write("当前页数是：" + CurrentPage + "<br />");

读取数据库第一条数据，有专门的读取方法。比如getValue方法，注意getValue方法是返回的是object类型，要转换。