asp.net(C#)海量数据表高效率分页算法

Tags: .net
 

首先创建一张表(要求ID自动编号):
create table redheadedfile(
id int identity(1,1),
filenames nvarchar(20),
senduser nvarchar(20),
primary key(id)
)
然后我们写入50万条记录:
declare @i int
set @i=1
while @i<=500000
begin
    insert into redheadedfile(filenames,senduser) values(我的分页算法,陆俊铭)
    set @i=@i+1
end
GO
用Microsoft Visual Studio .NET 2003创建一张WebForm网页(本人起名webform8.aspx)
前台代码片段如下(webform8.aspx):
<%@ Page language="c#" Codebehind="WebForm8.aspx.cs" AutoEventWireup="false" Inherits="WebApplication6.WebForm8" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
 <HEAD>
  <title>WebForm8</title>
  <meta content="Microsoft Visual Studio .NET 7.1" name="GENERATOR">
  <meta content="C#" name="CODE_LANGUAGE">
  <meta content="JavaScript" name="vs_defaultClientScript">
  <meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">
 </HEAD>
 <body MS_POSITIONING="GridLayout">
  <form id="Form1" method="post" runat="server">
   <asp:datalist id="datalist1" AlternatingItemStyle-BackColor="#f3f3f3" Width="100%" CellSpacing="0"
    CellPadding="0" Runat="server">
    <ItemTemplate>
     <table width="100%" border="0" cellspacing="0" cellpadding="0">
      <tr>
       <td width="30%"

align="center"><%#DataBinder.Eval(Container.DataItem,"filenames")%></td>
       <td width="30%"

align="center"><%#DataBinder.Eval(Container.DataItem,"senduser")%></td>
       <td width="30%"

align="center"><%#DataBinder.Eval(Container.DataItem,"id")%></td>
      </tr>
     </table>
    </ItemTemplate>
   </asp:datalist>
   <div align="center">共<asp:label id="LPageCount" Runat="server" ForeColor="#ff0000"></asp:label>页/共

<asp:label id="LRecordCount" Runat="server" ForeColor="#ff0000"></asp:label>记录
    <asp:linkbutton id="Fistpage" Runat="server"

CommandName="0">首页</asp:linkbutton>&nbsp;&nbsp;&nbsp;&nbsp;<asp:linkbutton id="Prevpage" Runat="server" CommandName="prev">

上一页</asp:linkbutton>&nbsp;&nbsp;&nbsp;&nbsp;<asp:linkbutton id="Nextpage" Runat="server"

CommandName="next">下一页</asp:linkbutton>&nbsp;&nbsp;&nbsp;&nbsp;<asp:linkbutton id="Lastpage" Runat="server"

CommandName="last">尾页</asp:linkbutton>&nbsp;&nbsp;&nbsp;&nbsp;当前第<asp:label id="LCurrentPage" Runat="server"

ForeColor="#ff0000"></asp:label>页&nbsp;&nbsp;&nbsp;&nbsp;跳页<asp:TextBox ID="gotoPage" Runat="server" Width="30px"

MaxLength="5" AutoPostBack="True"></asp:TextBox></div>
  </form>
 </body>
</HTML>
后台代码片段如下(webform8.aspx.cs)
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.Configuration;

namespace WebApplication6
{
 /// <summary>
 /// WebForm8 的摘要说明。
 /// </summary>
 public class WebForm8 : System.Web.UI.Page
 {
  protected System.Web.UI.WebControls.LinkButton Fistpage;
  protected System.Web.UI.WebControls.LinkButton Prevpage;
  protected System.Web.UI.WebControls.LinkButton Nextpage;
  protected System.Web.UI.WebControls.LinkButton Lastpage;
  protected System.Web.UI.WebControls.DataList datalist1;
  protected System.Web.UI.WebControls.DropDownList mydroplist;
  protected System.Web.UI.WebControls.Label LPageCount;
  protected System.Web.UI.WebControls.Label LRecordCount;
  protected System.Web.UI.WebControls.Label LCurrentPage;
  protected System.Web.UI.WebControls.TextBox gotoPage;
  const int PageSize=20;//定义每页显示记录
  int PageCount,RecCount,CurrentPage,Pages,JumpPage;//定义几个保存分页参数变量
 
  private void Page_Load(object sender, System.EventArgs e)
  {
   if(!IsPostBack)
   {
    RecCount = Calc();//通过Calc()函数获取总记录数
    PageCount = RecCount/PageSize + OverPage();//计算总页数(加上OverPage()函数防止有余数造成显示

数据不完整)

    ViewState["PageCounts"] = RecCount/PageSize -

ModPage();//保存总页参数到ViewState(减去ModPage()函数防止SQL语句执行时溢出查询范围,可以用存储过程分页算法来理解这句)
    ViewState["PageIndex"] = 0;//保存一个为0的页面索引值到ViewState
    ViewState["JumpPages"] = PageCount;//保存PageCount到ViewState,跳页时判断用户输入数是否超出页

码范围
    //显示LPageCount、LRecordCount的状态
    LPageCount.Text = PageCount.ToString();
    LRecordCount.Text = RecCount.ToString();
    //判断跳页文本框失效
    if(RecCount <= 20)
     gotoPage.Enabled = false;
    TDataBind();//调用数据绑定函数TDataBind()进行数据绑定运算
   }
  }
        //计算余页
  public int OverPage()
  {
   int pages = 0;
   if(RecCount%PageSize != 0)
    pages = 1;
   else
    pages = 0;
   return pages;
  }
        //计算余页,防止SQL语句执行时溢出查询范围
  public int ModPage()
  {
   int pages = 0;
   if(RecCount%PageSize == 0 && RecCount != 0)
    pages = 1;
   else
    pages = 0;
   return pages;
  }
        /*
   *计算总记录的静态函数
   *本人在这里使用静态函数的理由是:如果引用的是静态数据或静态函数,连接器会优化生成代码,去掉动态重定位项(对

海量数据表分页效果更明显)。
   *希望大家给予意见、如有不正确的地方望指正。
  */
  public static int Calc()
  {
   int RecordCount = 0;
   SqlCommand MyCmd = new SqlCommand("select count(*) as co from redheadedfile",MyCon());
   SqlDataReader dr = MyCmd.ExecuteReader();
   if(dr.Read())
    RecordCount = Int32.Parse(dr["co"].To

本文链接:http://www.4byte.cn/learning/87008.html