为DataGrid的自带分页添加首页、尾页及状态功能

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                    为DataGrid的自带分页添加首页、尾页及状态功能

         郑 佐 2004-9-20

DataGrid提供了分页功能,不过看上去功能有限,但是我们可以通过DataGrid的一些属性来获取状态以及增加首页、尾页功能按钮。这里没有使用DataGrid的自定义分页功能,如果在速度效率不是很讲究的情况下,由DataGrid自己管理分页还是不错的,付出的代价就是要把整个相关数据取出来后再删选指定页的数据。好处就是开发速度快,不需要写分页的存储过程。本文事例使用的是Sql Server中的Northwind数据库。运行界面如下:


对于前台的显示界面,我放了一个
DataGrid;四个LinkButton导向按钮;四个Literal来显示纪录状态。

剩下的就是用表格定位。

这里需要设置DataGridAllowPaging属性为True,同时设置AllowCustomPaging属性位false(默认为false),设置PagerStyleVisible属性为False,使前台不显示。

前台的代码如下:

<%@ Page language="c#" Codebehind="DataGridPaging.aspx.cs" AutoEventWireup="false" Inherits="ZZ.AspnetPaging.DataGridPaging" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >

<HTML>

     <HEAD>

         <title>DataGridPaging</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>

         <form id="Form1" method="post" runat="server">

              <TABLE id="Table1" style="FONT-SIZE: 9pt" cellSpacing="1" cellPadding="1" width="450" align="center"

                   border="1">

                   <TR>

                       <TD><asp:datagrid id="DataGrid1" runat="server" PageSize="5" Width="100%" AllowPaging="True">

                                 <HeaderStyle Font-Size="9pt"></HeaderStyle>

                                 <FooterStyle Font-Size="9pt"></FooterStyle>

                                 <PagerStyle Visible="False" Font-Size="9pt" Mode="NumericPages"></PagerStyle>

                            </asp:datagrid></TD>

                   </TR>

              </TABLE>

              <TABLE id="Table2" style="FONT-SIZE: 9pt" cellSpacing="1" cellPadding="1" width="450" align="center"

                   border="1">

                   <TR>

                       <TD style="WIDTH: 207px">

                            <asp:linkbutton id="LBtnFirst" runat="server" CommandName="First">首页</asp:linkbutton>

                            <asp:linkbutton id="LBtnPrev" runat="server" CommandName="Prev">上一页</asp:linkbutton> 

                            <asp:linkbutton id="LBtnNext" runat="server" CommandName="Next">下一页</asp:linkbutton>

                            <asp:linkbutton id="LBtnLast" runat="server" CommandName="Last">尾页</asp:linkbutton> </TD>

                       <TD>

                            <asp:literal id="LtlPageIndex" runat="server"></asp:literal>页 共

                            <asp:literal id="LtlPageCount" runat="server"></asp:literal>页 每页

                            <asp:literal id="LtlPageSize" runat="server"></asp:literal>条 共

                            <asp:literal id="LtlRecordCount" runat="server"></asp:literal>

                       </TD>

                   </TR>

              </TABLE>

         </form>

     </body>

</HTML>

后台cs文件代码,DataGridPaging类从System.Web.UI.Page继承,在数据绑定时需要注意没有数据的情况(0页时),以及当页数减少时避免前台正在反页导致缺页。

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 ZZ.AspnetPaging

{

     public class DataGridPaging : System.Web.UI.Page

     {

         private static string connString = ConfigurationSettings.AppSettings["ConnString"];

         private int recordCount;

         private int pageCount;

 

         protected System.Web.UI.WebControls.LinkButton LBtnFirst;

         protected System.Web.UI.WebControls.LinkButton LBtnPrev;

         protected System.Web.UI.WebControls.LinkButton LBtnNext;

         protected System.Web.UI.WebControls.LinkButton LBtnLast;

          protected System.Web.UI.WebControls.Literal LtlPageIndex;

         protected System.Web.UI.WebControls.Literal LtlPageCount;

         protected System.Web.UI.WebControls.Literal LtlPageSize;

         protected System.Web.UI.WebControls.Literal LtlRecordCount;

         protected System.Web.UI.WebControls.DataGrid DataGrid1;

    

         private void Page_Load(object sender, System.EventArgs e)

         {

              if(!Page.IsPostBack)

              {

                   DataGridDataBind();

              }

         }

 

         //绑定数据

         private void DataGridDataBind()

         {

              DataSet ds = GetCustomersData();

              recordCount = ds.Tables[0].Rows.Count;

              //获取当前的页数

              pageCount = (int)Math.Ceiling( recordCount * 1.0 / PageSize);

              //避免纪录从有到无时,并且已经进行过反页的情况下CurrentPageIndex > PageCount出错

              if(recordCount ==0)

              {

                   this.DataGrid1.CurrentPageIndex = 0;

              }

              else if(this.DataGrid1.CurrentPageIndex >= pageCount)

              {

                   this.DataGrid1.CurrentPageIndex = pageCount - 1;

              }

              this.DataGrid1.DataSource = ds;

              this.DataGrid1.DataBind();

              NavigationStateChange();

         }

 

         #region Web 窗体设计器生成的代码

         override protected void OnInit(EventArgs e)

         {

              //

              // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。

              //

              InitializeComponent();

              base.OnInit(e);

         }

        

         /// <summary>

         /// 设计器支持所需的方法 - 不要使用代码编辑器修改

         /// 此方法的内容。

         /// </summary>

         private void InitializeComponent()

         {   

              this.LBtnFirst.Click += new System.EventHandler(this.LBtnNavigation_Click);

              this.LBtnPrev.Click += new System.EventHandler(this.LBtnNavigation_Click);

              this.LBtnNext.Click += new System.EventHandler(this.LBtnNavigation_Click);

              this.LBtnLast.Click += new System.EventHandler(this.LBtnNavigation_Click);

              this.Load += new System.EventHandler(this.Page_Load);

 

         }

         #endregion

 

         private void LBtnNavigation_Click(object sender, System.EventArgs e)

         {

              LinkButton btn = (LinkButton)sender;

              switch(btn.CommandName)

              {

                   case "First":

                       PageIndex = 0;

                       break;

                   case "Prev"://if( PageIndex > 0 )

                            PageIndex = PageIndex - 1;

                       break;

                   case "Next"://if( PageIndex < PageCount -1)

                            PageIndex = PageIndex + 1;

                       break;

                   case "Last":

                       PageIndex = PageCount - 1;

                       break;

              }

              DataGridDataBind();             

         }

         //数据绑定

         public static DataSet GetCustomersData()

         {

              SqlConnection conn = new SqlConnection(connString);

              string sqlStr = "SELECT CustomerID, CompanyName,Address,Phone FROM Customers";

              SqlCommand comm = new SqlCommand( sqlStr ,conn);

              SqlDataAdapter dataAdapter = new SqlDataAdapter(comm);

              DataSet ds = new DataSet();

              dataAdapter.Fill(ds);

              return ds;

         }

 

         /// <summary>

         /// 控制导航按钮或数字的状态

         /// </summary>

         public void NavigationStateChange()

         {

              if( PageCount <= 1 )//( RecordCount <= PageSize )//小于等于一页

              {

                   this.LBtnFirst.Enabled = false;

                   this.LBtnPrev.Enabled = false;

                   this.LBtnNext.Enabled = false;

                   this.LBtnLast.Enabled = false;

              }

              else //有多页

              {

                   if( PageIndex == 0 )//当前为第一页

                   {

                       this.LBtnFirst.Enabled = false;

                       this.LBtnPrev.Enabled = false;

                       this.LBtnNext.Enabled = true;

                       this.LBtnLast.Enabled = true;

                                    

                   }

                   else if( PageIndex == PageCount - 1 )//当前为最后页

                   {

                       this.LBtnFirst.Enabled = true;

                       this.LBtnPrev.Enabled = true;

                       this.LBtnNext.Enabled = false;

                       this.LBtnLast.Enabled = false;

                                    

                   }

                   else //中间页

                   {

                       this.LBtnFirst.Enabled = true;

                       this.LBtnPrev.Enabled = true;

                       this.LBtnNext.Enabled = true;

                       this.LBtnLast.Enabled = true;

                   }

                  

              }

              if(RecordCount == 0)//当没有纪录时DataGrid.PageCount会显示1

                   this.LtlPageCount.Text = "0";

              else

                   this.LtlPageCount.Text = PageCount.ToString();

              if(RecordCount == 0)

                   this.LtlPageIndex.Text = "0";

              else

                   this.LtlPageIndex.Text = (PageIndex + 1).ToString();//在有页数的情况下前台显示页数加1

              this.LtlPageSize.Text = PageSize.ToString();

              this.LtlRecordCount.Text = RecordCount.ToString();

         }

 

        

         // 总页数

         public int PageCount

         {

              get{return this.DataGrid1.PageCount;}

         }

         //页大小

         public int PageSize

         {

              get{return this.DataGrid1.PageSize;}

         }

         //页索引,从零开始

         public int PageIndex

         {

              get{return this.DataGrid1.CurrentPageIndex;}

              set{this.DataGrid1.CurrentPageIndex = value;}

         }

         // 纪录总数

         public int RecordCount

         {

              get{return recordCount;}

              set{recordCount = value;}

         }

     }

}

 

如果需要追求执行效率,而且数据量比较大的情况下建议使用DataGrid的自定义分页功能。存储过程执行只取一页的情况。如果有什么好的建议或发现问题请在Blog上留言。

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