Web用户控件开发--分页控件

分页是Web应用程序中最常用到的功能之一，在asp.net中，虽然自带了一些可以分页的数据控件，但其分页功能并不尽如人意。本文对于这些数据控件的假分页暂且不表，如有不明白的同学请百Google度之。

本文中实现的分页控件是在手动分页基础上做的改善，将分页实现的逻辑部分和数据控件的绑定尽可能分开，以克服手工编写分页代码任务繁琐、代码重用率低等问题。

本文依旧是一粒粟子。

一、分页控件素颜

二、分页控件的实现

本文中将介绍两种将分页实现逻辑与数据控件绑定分离的实现方式：

• 使用反射机制
• 使用事件机制

1、基于反射机制的分页控件

源码：

PagingHelper.ascx：

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="PagingHelper.ascx.cs" Inherits="PagingHelper.Controls.PagingHelper" %>

<div style="width:100%">

    <asp:LinkButton ID="lbtnFirstPage" runat="server" CausesValidation="false" onclick="lbtnPage_Click"  >首页</asp:LinkButton>

    <asp:LinkButton ID="lbtnPRevPage" runat="server" CausesValidation="false"  onclick="lbtnPage_Click" >上一页</asp:LinkButton>

    &nbsp;第<asp:Label ID="lbPageIndex" runat="server" Text=""></asp:Label>

    页/共<asp:Label ID="lbTotalPages" runat="server" Text=""></asp:Label>

    页 

    <asp:LinkButton ID="lbtnNextPage" runat="server" CausesValidation="false"  onclick="lbtnPage_Click" >下一页</asp:LinkButton>

    <asp:LinkButton ID="lbtnLastPage" runat="server" CausesValidation="false"  onclick="lbtnPage_Click" >尾页</asp:LinkButton>

</div>

PagingHelper.ascx.cs：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.HtmlControls;

using System.Reflection;

namespace PagingHelper.Controls

{

    public partial class PagingHelper : System.Web.UI.UserControl

    {

        #region 属性

        private int m_PageSize;

        public int PageSize         //每页显示记录数

        {

            set

            {

                m_PageSize = value;

            }

            get

            {

                if (m_PageSize.Equals(0))

                {

                    m_PageSize = 10;

                }

                return m_PageSize;

            }

        }

        private int m_PageIndex;

        public int PageIndex        //当前页页码

        {

            set

            {

                m_PageIndex = value;

            }

            get

            {

                if (m_PageIndex.Equals(0))

                {

                    m_PageIndex = 1;

                }

                return m_PageIndex;

            }

        }

        public int TotalItemCount   //记录总数

        {

            set;

            private get;

        }

        public string BindDataMethodName    //绑定数据的方法名

        {

            set;

            private get;

        }

        #endregion

        #region 受保护的方法

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            {

                BindPagingHelperControl();

            }

        }

        protected void lbtnPage_Click(object sender, EventArgs e)

        {

            LinkButton lbtn = sender as LinkButton;

            ReBindData(lbtn.CommandArgument);

        }

        #endregion

        #region 公共方法

        #endregion

        #region 私有方法

        private void BindPagingHelperControl()

        {

            int totalPages = (TotalItemCount % PageSize) == 0 ? TotalItemCount / PageSize : TotalItemCount / PageSize + 1;

            //显示

            lbPageIndex.Text = PageIndex.ToString();

            lbTotalPages.Text = totalPages.ToString();

            //使能

            lbtnFirstPage.Enabled = PageIndex > 1;

            lbtnPrevPage.Enabled =  PageIndex > 1;

            lbtnLastPage.Enabled = PageIndex < totalPages;

            lbtnNextPage.Enabled = PageIndex < totalPages;

            //命令

            lbtnFirstPage.CommandArgument = "1";

            lbtnPrevPage.CommandArgument = (PageIndex - 1).ToString();

            lbtnNextPage.CommandArgument = (PageIndex + 1).ToString();

            lbtnLastPage.CommandArgument = totalPages.ToString();

        }

        private void ReBindData(string pageIndex)

        {

            PageIndex = int.Parse(pageIndex);

            Object obj = null;  //空间所在的容器

            if (base.Parent is HtmlForm)

            {

                obj = this.Page;

            }

            else if (base.Parent is ContentPlaceHolder)

            {

                obj = this.Page.Master.Page;

            }

            else

            {

                obj = base.Parent;

            }

            MethodInfo methodInfo = obj.GetType().GetMethod(BindDataMethodName, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);

            methodInfo.Invoke(obj, null);

            BindPagingHelperControl();

        }

        #endregion

    }

}

Demo：

Default.aspx：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="PagingHelper.Default" %>

<%@ Register src="Controls/PagingHelper.ascx" tagname="PagingHelper" tagprefix="uc1" %>

<!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></title>

</head>

<body>

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

    <div>

        <asp:GridView ID="gvDemo" runat="server">

        </asp:GridView>

        <br />

        <uc1:PagingHelper ID="PagingHelper1" runat="server" PageSize="2" />

    </div>

    </form>

</body>

</html>

Default.aspx.cs：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Data;

namespace PagingHelper

{

    public partial class Default : System.Web.