📄 自定义分页.txt

📁 C# 是创新性的新式编程语言
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AllowPaging和AllowCustomPaging设置为true
并提供PageIndexChanged事件的代码

1.页面
<%@ Page language="c#" Codebehind="WebForm12.aspx.cs" AutoEventWireup="false" Inherits="Co_112.WebForm12" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
	<HEAD>
		<title>WebForm12</title>
		<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
		<meta name="CODE_LANGUAGE" Content="C#">
		<meta name="vs_defaultClientScript" content="JavaScript">
		<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
	</HEAD>
	<body MS_POSITIONING="GridLayout">
		<form id="Form1" method="post" runat="server">
			<asp:Label id="Label1" style="Z-INDEX: 101; LEFT: 32px; POSITION: absolute; TOP: 24px" runat="server">自定义分页</asp:Label>
			<asp:DataGrid id="DataGrid1" style="Z-INDEX: 102; LEFT: 112px; POSITION: absolute; TOP: 80px"
				runat="server" AllowCustomPaging="True" AllowPaging="True" PageSize="2" AutoGenerateColumns="False">
				<Columns>
					<asp:BoundColumn DataField="employeeid" HeaderText="ID"></asp:BoundColumn>
					<asp:BoundColumn DataField="firstname" HeaderText="FirstName"></asp:BoundColumn>
					<asp:BoundColumn DataField="lastname" HeaderText="Lastname"></asp:BoundColumn>
				</Columns>
			</asp:DataGrid>
		</form>
	</body>
</HTML>

2.代码
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.Text;
namespace Co_112
{
	/// <summary>
	/// WebForm12 的摘要说明。
	/// </summary>
	public class WebForm12 : System.Web.UI.Page
	{
		protected System.Web.UI.WebControls.Label Label1;
		protected System.Web.UI.WebControls.DataGrid DataGrid1;
	
		private void Page_Load(object sender, System.EventArgs e)
		{
			if(!Page.IsPostBack)
			{
				SetVirtualItemCount();
				DataGrid1.DataSource=CreateDataSource(1);//第1页
				DataGrid1.CurrentPageIndex=0;//索引为0
				DataGrid1.DataBind();				
			}
		}
		//设置实际的项数
		public void SetVirtualItemCount()
		{
			//建立连接
			string strConn="Server=localhost;Database=northwind;uid=sa;pwd=;";
			SqlConnection conn=new SqlConnection(strConn);
			//设置命令
			string strCmd="Select Count(*) From Employees";
			SqlCommand cmd=new SqlCommand(strCmd,conn);
			//执行命令
			conn.Open();
			int nItemCount=(int)cmd.ExecuteScalar();//返回结果集的第一行第一列，忽略其它
			conn.Close();
			//设置网格的实际项数
			DataGrid1.VirtualItemCount=nItemCount;
		}

		#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.DataGrid1.PageIndexChanged += new System.Web.UI.WebControls.DataGridPageChangedEventHandler(this.DataGrid1_PageIndexChanged);
			this.Load += new System.EventHandler(this.Page_Load);

		}
		#endregion

		private void DataGrid1_PageIndexChanged(object source, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)
		{
			bool IsNext=false;//向前或向后
			if(DataGrid1.CurrentPageIndex<e.NewPageIndex)
				IsNext=true;
			else
				IsNext=false;
			if(DataGrid1.CurrentPageIndex==0&&IsNext)//当前索引为0时用户第一次按向后(Next)键
				DataGrid1.CurrentPageIndex=e.NewPageIndex+1;
			else 
				DataGrid1.CurrentPageIndex=e.NewPageIndex;
			DataGrid1.DataSource=CreateDataSource(DataGrid1.CurrentPageIndex);
			if(DataGrid1.CurrentPageIndex==1&&!IsNext)//当前索引为1时用户第一次按向前(Prev)键
				DataGrid1.CurrentPageIndex=0;
			DataGrid1.DataBind();
		}
		private SqlDataReader CreateDataSource(int nPageIndex)
		{
			int nPageSize=DataGrid1.PageSize;
			int nBaseProductID=nPageSize*nPageIndex;
			//建立连接
			string strConn="Server=localhost;Database=northwind;uid=sa;pwd=;";
			SqlConnection conn=new SqlConnection(strConn);
			//设置命令(三个嵌套的Select)
			StringBuilder sb=new StringBuilder("");
			sb.Append("Select Top {0} * From ");
			sb.Append("(Select Top {0} employeeid,firstname,lastname ");
			sb.Append("From Employees Where {1} In ");
			sb.Append("(Select Top {2} {1} From Employees Order By {1})");
			sb.Append("Order by {1} Desc) As temp ");
			sb.Append("Order by {1}");
			String strCmd=sb.ToString();
			//实际数据取得占位符
			int nRowsToDisplay=DataGrid1.PageSize;
			int nMod=DataGrid1.VirtualItemCount%DataGrid1.PageSize;
			if(nPageIndex==DataGrid1.PageCount&&nMod>0)
				nRowsToDisplay=nMod;
			string strCurrentSortExpr="employeeid";//排序关键字
			strCmd=String.Format(strCmd,nRowsToDisplay,strCurrentSortExpr,
				DataGrid1.PageSize*nPageIndex);

			SqlCommand cmd=new SqlCommand(strCmd,conn);
			conn.Open();
			SqlDataReader dr;
			dr=cmd.ExecuteReader(CommandBehavior.CloseConnection);
			return dr;
		}
	}
}
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