datalist控件的分页（下载示例与自己改写示例）

最新推荐文章于 2017-11-06 02:44:00 发布

wygyhm

最新推荐文章于 2017-11-06 02:44:00 发布

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分类专栏： asp.net 文章标签： asp exception server dataset textbox string

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本文介绍如何在ASP.NET中实现DataList控件的分页功能，并结合超级链接进行页面导航。通过示例代码展示了从数据库获取数据、计算总页数及当前页数的过程，以及使用ViewState保持状态的方法。

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1、参考示例

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="test.aspx.cs" Inherits="News_test" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns=" http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <TABLE id="Table1" style="Z-INDEX: 101; LEFT: 32px; WIDTH: 752px; POSITION: absolute; TOP: 16px; HEIGHT: 312px" cellSpacing="0" cellPadding="0" width="752" border="0">
            <TR>
                <TD style="HEIGHT: 29px"><FONT">宋体">DataList分页技术和超级链接</FONT></TD>
            </TR>
            <TR>
                <TD style="HEIGHT: 252px">
                <asp:datalist id="DataList1" runat="server" Width="576px" Height="96px">
                     <HeaderTemplate>
                            定单编号<td>
                            员工编号<td>
                            定单日期<td>
                            运费<td>
                            运往所在城市
                     </HeaderTemplate>

            <asp:linkbutton id="FirstLB" runat="server" OnCommand="LinkButton_Click" CommandName="first">第一页</asp:linkbutton> 
            <asp:linkbutton id="PreviousLB" runat="server" OnCommand="LinkButton_Click" CommandName="prev">上一页</asp:linkbutton> 
            <asp:linkbutton id="NextLB" runat="server" OnCommand=LinkButton_Click CommandName="next">下一页</asp:linkbutton> 
            <asp:linkbutton id="EndLB" runat="server" OnCommand=LinkButton_Click CommandName="end">最后一页</asp:linkbutton>  
            总<asp:label id="TotalLbl" runat="server"></asp:label>页当前第<asp:label id="CurrentLbl" runat="server"></asp:label>页
            <asp:linkbutton id="JumpLB" runat="server" OnCommand=LinkButton_Click CommandName="jump">跳到</asp:linkbutton>第
            <asp:textbox id="TextBox1" runat="server" Width="90px"></asp:textbox>
            页</FONT></TD>
            </TR>
            </TABLE>
    </div>
    </form>
</body>
</html>

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

public partial class News_test : System.Web.UI.Page
{
    int CurrentPage;//当前页数
    int PageSize;   //每页条数
    int PageCount; //总页数
    int RecordCount;//总条数
    private void Page_Load(object sender, System.EventArgs e)
    {
        // 在此处放置用户代码以初始化页面

        PageSize = 10;//每页10条记录
        if (!Page.IsPostBack)
        {
             CurrentPage = 0;//当前页习惯设为0
            ViewState["PageIndex"] = 0;//页索引也设为0

//计算总共有多少记录
RecordCount = CalculateRecord();

//计算总共有多少页
            if (RecordCount % PageSize == 0)
            {
                PageCount = RecordCount / PageSize;
            }
            else
            {
                PageCount = RecordCount / PageSize + 1;
            }

this.TotalLbl.Text = PageCount.ToString();//显示总页数
ViewState["PageCount"] = PageCount;//会话session 对整个 application 有效，而视图状态 viewstate相当于某个页面的 session

this.DataListBind();//不可以放在初始化条件之前就绑定，那样的话，如果仅有一页的数据，“下一页”页仍然显示
}

}

    //计算总共有多少条记录
    private int CalculateRecord()
    {
        try
        {
            int recordCount;
            SqlConnection con = new SqlConnection("server=127.0.0.1;database=Northwind;uid=sa;pwd=sa");//数据库使用Northwind;
            con.Open();

            string sql = "select count(*) as count from Orders";
            SqlCommand cmd = new SqlCommand(sql, con);
            SqlDataReader sdr = cmd.ExecuteReader();

            if (sdr.Read())
            {
                recordCount = Int32.Parse(sdr["count"].ToString());
            }

            else
            {
                recordCount = 0;
            }

            sdr.Close();
            con.Close();
            return recordCount;
        }

        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }

    //将数据绑定到Datalist控件
    public void DataListBind()
    {
        try
        {
            int StartIndex = CurrentPage * PageSize;//设定导入的起终地址
            string sql = "select * from Orders";
            DataSet ds = new DataSet();
           SqlConnection con = new SqlConnection("server=127.0.0.1;database=Northwind;uid=sa;pwd=sa");
            con.Open();

            SqlDataAdapter sda = new SqlDataAdapter(sql, con);
            sda.Fill(ds, StartIndex, PageSize, "orders");//这是sda.Fill方法的第一次重载，里面的变量分别是数据集DataSet ,开始记录数StartRecord，最大的记录数MaxRecord，数据表名TableName
            this.DataList1.DataSource = ds.Tables["orders"].DefaultView;
            this.DataList1.DataBind();
            this.PreviousLB.Enabled = true;
            this.NextLB.Enabled = true;
            if (CurrentPage == (PageCount - 1)) this.NextLB.Enabled = false;//当为最后一页时，下一页链接按钮不可用
            if (CurrentPage == 0) this.PreviousLB.Enabled = false;//当为第一页时，上一页按钮不可用
            this.CurrentLbl.Text = (CurrentPage + 1).ToString();//当前页数

}

        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }

    public void LinkButton_Click(Object sender, CommandEventArgs e)//自己编写的按钮点击事件
    {
        CurrentPage = (int)ViewState["PageIndex"];//获得当前页索引
        PageCount = (int)ViewState["PageCount"];//获得总页数

string cmd = e.CommandName;

//判断cmd，以判定翻页方向

        switch (cmd)
        {
            case "prev"://上一页
                if (CurrentPage > 0) CurrentPage--;
                break;

            case "next":
                if (CurrentPage < (PageCount - 1)) CurrentPage++;//下一页
                break;

            case "first"://第一页
                CurrentPage = 0;
                break;

            case "end"://最后一页
                CurrentPage = PageCount - 1;
                break;

            case "jump"://跳转到第几页
                if (this.TextBox1.Text.Trim() == "" || Int32.Parse(this.TextBox1.Text.Trim()) > PageCount)//如果输入数字为空或超出范围则返回
                {
                    return;
                }
                else
                {
                    CurrentPage = Int32.Parse(this.TextBox1.Text.ToString()) - 1;
                    break;
                }
        }
        ViewState["PageIndex"] = CurrentPage;//获得当前页

this.DataListBind();//重新将DataList绑定到数据库

}

}

2、自己改写示例

<% @ Page Language="C#" AutoEventWireup="true" CodeFile="newslist.aspx.cs" Inherits="newslist" %>

<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >

< html xmlns ="http://www.w3.org/1999/xhtml" >

< head runat ="server" >

< title > 新闻列表 </ title >

</ head >

< body >

< form id ="form1" runat ="server" >

< div >

< table >

< tr >

< td style ="width: 618px" >

< asp:Label ID ="Label2" runat ="server" Text ="Label" Width ="427px" ></ asp:Label ></ td >

</ tr >

< tr >

< td style ="width: 618px; height: 223px" >

< asp:DataList ID ="DataList1" runat ="server" Width ="615px" >

< ItemTemplate >

< table >

< tr >

< td style ="width: 25px; height: 22px; color: blue;" >

• </ td >

< td style ="width: 1552px; height: 22px" >

< asp:LinkButton ID ="LinkButton1" runat ="server" > <% #DataBinder.Eval(Container.DataItem,"title") %> </ asp:LinkButton ></ td >

< td style ="width: 438px; height: 22px" >

< asp:Label ID ="Label1" runat ="server" > <% #((DateTime)DataBinder.Eval(Container.DataItem, "adddate")).ToShortDateString() %> </ asp:Label ></ td >

</ tr >

</ table >

</ ItemTemplate >

</ asp:DataList ></ td >

</ tr >

< tr >

< td style ="width: 618px; text-align: center;" >

< asp:Label ID ="lbpage" runat ="server" Text ="Label" ></ asp:Label >

    < asp:LinkButton ID ="lbfirst" runat ="server" CommandName ="first" OnCommand ="linkbuttoncmd" > 首页 </ asp:LinkButton >

< asp:LinkButton ID ="lbprev" runat ="server" CommandName ="prev" OnCommand ="linkbuttoncmd" > 上一页 </ asp:LinkButton >

< asp:LinkButton ID ="lbnext" runat ="server" CommandName ="next" OnCommand ="linkbuttoncmd" > 下一页 </ asp:LinkButton >

< asp:LinkButton ID ="lblast" runat ="server" CommandName ="last" OnCommand ="linkbuttoncmd" > 末页 </ asp:LinkButton >  

< asp:TextBox ID ="tb" runat ="server" Width ="46px" ></ asp:TextBox >

< asp:LinkButton ID ="lbjump" runat ="server" CommandName ="jump" OnCommand ="linkbuttoncmd" > 跳转 </ asp:LinkButton ></ td >

</ tr >

</ table >

</ div >

</ form >

</ body >

</ html >

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

public partial class newslist : System.Web.UI.Page

{

BaseClass bc=new BaseClass();

pagechange pc = new pagechange();

string strstyle;

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

int n = Convert.ToInt32(Request.QueryString["id"]);

switch (n)

{

case 1: strstyle = "type='企业新闻'";

Label2.Text = "足不出户－＞企业新闻";

break;

case 2: strstyle = "type='行业新闻'";

Label2.Text = "足不出户－＞行业新闻";

break;

case 3: strstyle = "type='社会新闻'";

Label2.Text = "足不出户－＞社会新闻";

break;

default: strstyle = "type like '%%'";

Label2.Text = "所有新闻";

break;

}

pc.cmd = "select count(*) as count from tbnews where " + strstyle;

pc.RecordCount();

pc.PageCount();

pc.sql = "select * from tbnews where " + strstyle;

pc.databind(DataList1, lbprev, lbnext, lbpage);

//与 Session 的重要区别有两个：

//第一、ViewState 保存的对象不能跨页使用，仅限当前页面使用。Session 对象则可以所有页面共享使用。

//第二、Session 的变量存储在服务器上，ViewState 存储在当前页面中。

ViewState["pagecount"] = pc.pagecount;//ViewState 保存的对象不能跨页使用,仅限当前页面使用.而

ViewState["currentpage"] = pc.currentpage;

ViewState["sql"] = pc.sql;

}

else

{

pc.pagecount = int.Parse(ViewState["pagecount"].ToString());

pc.currentpage = int.Parse(ViewState["currentpage"].ToString());

pc.sql = ViewState["sql"].ToString();

}

protected void linkbuttoncmd(Object sender, CommandEventArgs e)//自己编写的按钮点击事件

{

switch (e.CommandName)

{

case "first":

pc.currentpage = 0;

break;

case "prev":

if (pc.currentpage > 0) { pc.currentpage = pc.currentpage - 1; }

break;

case "next":

if (pc.currentpage < pc.pagecount - 1) { pc.currentpage = pc.currentpage + 1; }

break;

case "last":

pc.currentpage = pc.pagecount - 1;

break;

case "jump":

if (tb.Text.Trim() == "" || int.Parse(tb.Text.Trim()) < 0 & int.Parse(tb.Text.Trim()) > pc.pagecount - 1)

{

return;

}

else

{

pc.currentpage = int.Parse(tb.Text.Trim()) - 1;

}

break;

}

ViewState["currentpage"] = pc.currentpage;

pc.databind(DataList1, lbprev, lbnext, lbpage);

}

protected void DataList1_ItemCommand(object source, DataListCommandEventArgs e)

{

string id = DataList1.DataKeys[e.Item.ItemIndex].ToString();

Response.Write("<script language=javascript>window.open('showNews.aspx?id=" + id + "','','width=520,height=260')</script>");

}

pagechange类

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

/// <summary>
/// pagechange 的摘要说明
/// </summary>
public class pagechange
{
    SqlConnection cnn = new SqlConnection(ConfigurationManager.AppSettings["constr"]);
    public int _recordcount;//定义记录数
    public int _pagecount;//定义页数
    public string _cmd;
    public string _sql;
    public int _pagesize = 10;//每页显示的记录数
    public int _currentpage = 0;//当前页的索引

   public pagechange()
{
  //
  // TODO: 在此处添加构造函数逻辑
  //
}

    //定义有关的属性
    public int recordcount
    {
        get { return _recordcount; }
        set { _recordcount = value; }
    }
    public int pagecount
    {
        get { return _pagecount; }
        set { _pagecount = value; }
    }

    public string cmd
    {
        get { return _cmd; }
        set { _cmd = value; }
    }
    public string sql
    {
        get { return _sql; }
        set { _sql = value; }
    }
    public int pagesize
    {
        get { return _pagesize; }
        set { _pagesize = value; }
    }

    public int currentpage
    {
        get { return _currentpage; }
        set { _currentpage = value; }
    }

    //创建获得记录总数的方法
    public int RecordCount()
    {
        try
        {
            cnn.Open();
            SqlCommand sqlcmd = new SqlCommand(cmd, cnn);
            SqlDataReader sr = sqlcmd.ExecuteReader();//将 CommandText 发送到 Connection 并生成一个 SqlDataReader。
            if (sr.Read())//使 SqlDataReader 前进到下一条记录。SqlDataReader 的默认位置在第一条记录的前面。读取到最后一条记录的后面返回false.
            {
                recordcount = int.Parse(sr["count"].ToString());
                sr.Close();
                return recordcount;
            }
            else
            {
                recordcount = 0;
                return recordcount;
            }
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
        finally
        {
            cnn.Close();
        }
    }

    //创建获得页数的方法
    public int PageCount()
    {
        try
        {
            if (recordcount % pagesize == 0)
            {
                pagecount = recordcount / pagesize;
                return pagecount;
            }
            else
            {
                pagecount = recordcount / pagesize + 1;
                return pagecount;
            }
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }

    //绑定数据
    public void databind(DataList dl, LinkButton lbprev, LinkButton lbnext, Label lb)
    {
        try
        {
            cnn.Open();
            SqlDataAdapter da = new SqlDataAdapter(sql, cnn);
            DataSet ds = new DataSet();
            int startindex = pagesize * currentpage;//每页的第一条记录的索引
            da.Fill(ds, startindex, pagesize, "tbnews");
            //DataAdapter的Fill方法的重载形式，即将从da的startinde索引位置开始的pagesize条记录添加到内存ds名为 "tbNews"的表中。
            dl.DataSource = ds.Tables[0].DefaultView;//相当于dl.DataSource = ds.Tables["tbnews"].DefaultView;
            dl.DataKeyField = "id";
            dl.DataBind();
            lbprev.Enabled = true;
            lbnext.Enabled = true;
            if (currentpage == 0)
            {
                lbprev.Enabled = false;
            }
            if (currentpage == pagecount - 1)
            {
                lbnext.Enabled = false;
            }
            int page = currentpage + 1;//返回当前页号，因为页是基于索引0的，所以要加1，才符合一般的习惯
            lb.Text = page.ToString() + " of " + pagecount.ToString();

        }
        catch (Exception ex)
        { throw new Exception(ex.Message); }
        finally
        { cnn.Close(); }
    }

}