本文讲述的是如何利用 XMLHttpRequest 来对 Repeater 控件 进行无刷新分页。
实现的方式是，使用XMLHttpRequest对象异步向服务器发送post 请求，传递设置好的每页显示记录数，当前页码和记录总数。服务器端接收到请求时，根据参数从数据库中查询相应记录，并通过Repeater 控件将数据显示出来，然后调用Repeater 的RenderControl 方法 将Repeater 绑定后生成的HTML代码作为服务器端的响应文本返回给客户端，客户端接到响应后替换Repeater 的相应HTML代码，从而实现了Repeater 无刷新分页。
需要注意的地方：
1、显示首页记录时，首页和上一页不可用，同理，显示末页记录时，末页和下一页不可用。
2、重新设置每页显示记录数时，要保持当前的页码不变，分页数改变。
下面看代码实现:
首先，创建一个WEB窗体，命名为 RepeaterDemo.aspx
代码如下:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="RepeaterDemo.aspx.cs" Inherits="RepeaterDemo" %>
<!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>
<style>
<!--
.n{TEXT-DECORATION:none;cursor:pointer} a{color:black} a:hover{color:blue}
.m{TEXT-DECORATION:none;cursor:default} a{color:black}
//-->
</style>
<script type="text/javascript">
var xmlHttp=null;
var index,size="10";
function $(id)
{
return document.getElementById(id);
}
function createXMLHttpRequest()
{
if(xmlHttp == null){
if(window.XMLHttpRequest) {
//Mozilla 浏览器
xmlHttp = new XMLHttpRequest();
}else if(window.ActiveXObject) {
// IE浏览器
try {
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {
alert('创建失败');
}
}
}
}
}
function openAjax(para)
{
if( xmlHttp == null)
{
createXMLHttpRequest();
if( xmlHttp == null)
{
alert('出错');
return ;
}
}
xmlHttp.open("post","RepeaterDemoResult.aspx?date="+new Date().getTime(),true);
xmlHttp.onreadystatechange=xmlHttpChange;
xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
xmlHttp.send(para);
}
function xmlHttpChange()
{
if(xmlHttp.readyState==4)
{
if(xmlHttp.status==200)
{
$('resultDiv').innerHTML=xmlHttp.responseText;
$('<%=lblCurrentPage.ClientID %>').innerText=index==null?$('<%=lblCurrentPage.ClientID %>').innerText:index;
if(index==1)
{
$('<%=lbtnFirst.ClientID %>').disabled=true;
$('<%=lbtnPrevious.ClientID %>').disabled=true;
$('<%=lbtnFirst.ClientID %>').className='m';
$('<%=lbtnPrevious.ClientID %>').className='m';
}
else
{
$('<%=lbtnFirst.ClientID %>').disabled='';
$('<%=lbtnPrevious.ClientID %>').disabled='';
$('<%=lbtnFirst.ClientID %>').className='n';
$('<%=lbtnPrevious.ClientID %>').className='n';
}
if(index==document.getElementById('<%=lblPageCount.ClientID %>').innerText)
{
$('<%=lbtnNext.ClientID %>').disabled=true;
$('<%=lbtnLast.ClientID %>').disabled=true;
$('<%=lbtnNext.ClientID %>').className='m';
$('<%=lbtnLast.ClientID %>').className='m';
}
else
{
$('<%=lbtnNext.ClientID %>').disabled=false;
$('<%=lbtnLast.ClientID %>').disabled=false;
$('<%=lbtnNext.ClientID %>').className='n';
$('<%=lbtnLast.ClientID %>').className='n';
}
}
}
}
function getHTML(operate)
{
if(event.srcElement.disabled)
{
return;
}
var currentPage;
var pageSize=$('<%=txtPageSize.ClientID %>').value;
var count=$('<%=lblCount.ClientID %>').innerText;
if(operate=='f')
{
currentPage=1;
}
else if(operate=='p')
{
currentPage=parseInt($('<%=lblCurrentPage.ClientID %>').innerText)-1;
}
else if(operate=='n')
{
currentPage=parseInt($('<%=lblCurrentPage.ClientID %>').innerText)+1;
}
else if(operate=='l')
{
currentPage=$('<%=lblPageCount.ClientID %>').innerText;
}
else if(operate=='c')
{
currentPage=$('<%=lblCurrentPage.ClientID %>').innerText;
if(pageSize==size)
{
return ;
}
size=pageSize;
}
else
{
return ;
}
index=currentPage;
var para="pageNum="+currentPage+"&pageSize="+pageSize+"&count="+count;
openAjax(para);
}
function verify()
{
if(isNaN(parseInt($('<%=txtPageSize.ClientID %>').value)))
{
alert('请输入数字！');
return false;
}
getHTML('c');
var count=parseInt($('<%=lblCount.ClientID %>').innerText);
if(isNaN(count))
{
return;
}
var pageCount=(count%size==0)?count/size:(count-(count%size))/size+1;
$('<%=lblPageCount.ClientID %>').innerText=pageCount;
var temp=parseInt($('<%=lblCurrentPage.ClientID %>').innerText);
if(pageCount<temp)
{
$('<%=lblCurrentPage.ClientID %>').innerText=pageCount;
index=pageCount;
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div id='resultDiv' style="cursor:auto">
<asp:Repeater ID="rp" runat="server">
<HeaderTemplate>
<table><tr><td>编号</td><td>名称</td><td>价格</td><td>库存</td></tr>
</HeaderTemplate>
<AlternatingItemTemplate><tr><td><%#Eval("ProductID") %></td><td><%#Eval("ProductName") %></td><td><%#Eval("UnitPrice") %></td><td><%#Eval("UnitsInStock") %></td></tr></AlternatingItemTemplate>
<ItemTemplate><tr><td><%#Eval("ProductID") %></td><td><%#Eval("ProductName") %></td><td><%#Eval("UnitPrice") %></td><td><%#Eval("UnitsInStock") %></td></tr></ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
</div>
每页显示<asp:TextBox ID="txtPageSize" runat="server" Text="10"></asp:TextBox>条记录 <input type="button" value="设置" onclick="return verify();" /><br />
记录总数为:<asp:Label ID="lblCount" runat="server"></asp:Label>
共分<asp:Label ID="lblPageCount" runat="server"></asp:Label>页
当前为第<asp:Label ID="lblCurrentPage" runat="server"></asp:Label>页<br />
<asp:LinkButton ID="lbtnFirst" CssClass='n' OnClientClick="getHTML('f');return false;" Text="首页" runat="server"></asp:LinkButton>
<asp:LinkButton ID="lbtnPrevious" CssClass='n' OnClientClick="getHTML('p');return false;" Text="上页" runat="server"></asp:LinkButton>
<asp:LinkButton ID="lbtnNext" CssClass='n' OnClientClick="getHTML('n');return false;" Text="下页" runat="server"></asp:LinkButton>
<asp:LinkButton ID="lbtnLast" CssClass='n' OnClientClick="getHTML('l');return false;" Text="末页" runat="server"></asp:LinkButton>
</form>
</body>
</html>
.cs 代码
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;
using System.Text;
public partial class RepeaterDemo : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
using (SqlConnection con=new SqlConnection("server=.;uid=sa;pwd=sa;database=Northwind"))
{
SqlDataAdapter sda = new SqlDataAdapter("select count(*) from products", con);
DataSet ds = new DataSet();
sda.Fill(ds, "productsCount");
lblCount.Text = ds.Tables["productsCount"].Rows[0][0].ToString();
sda = new SqlDataAdapter("select * from products", con);
int count, pageCount, pageSize,currentPage;
int.TryParse(txtPageSize.Text, out pageSize);
pageSize = pageSize == 0 ? 10 : pageSize;
int.TryParse(lblCount.Text, out count);
pageCount = count % pageSize == 0 ? count / pageSize : count / pageSize + 1;
lblPageCount.Text = pageCount.ToString();
sda.Fill(ds, 0, pageSize, "products");
lblCurrentPage.Text = "1";
currentPage = 1;
rp.DataSource = ds.Tables["products"].DefaultView;
rp.DataBind();
//lbtnFirst.Enabled = false;
//lbtnPrevious.Enabled = false;
StringBuilder sb = new StringBuilder();
sb.Append("document.getElementById('" + lbtnFirst.ClientID + "').disabled=true;");
sb.Append("document.getElementById('" + lbtnPrevious.ClientID + "').disabled=true;"); if (pageCount == currentPage)
{
//lbtnNext.Enabled = false;
//lbtnLast.Enabled = false;
sb.Append("document.getElementById('" + lbtnNext.ClientID + "').disabled=true;");
sb.Append("document.getElementById('" + lbtnLast.ClientID + "').disabled=true;");
}//end if block
ClientScript.RegisterStartupScript(GetType(), "disabled", "<script>" + sb.ToString() + "</script>");
}//end using block
}//end if block
}//end Page_Load event
}
然后创建服务器端接收XMLHttpRequest 请求的文件，这里用的是WEB窗体，命名为 RepeaterDemoResult.aspx
.aspx 代码如下:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="RepeaterDemoResult.aspx.cs" Inherits="RepeaterDemoResult" %>
<!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">
<asp:Repeater ID="rp" runat="server">
<HeaderTemplate>
<table><tr><td>编号</td><td>名称</td><td>价格</td><td>库存</td></tr>
</HeaderTemplate>
<AlternatingItemTemplate>
<tr><td><%#Eval("ProductID") %></td><td><%#Eval("ProductName") %></td><td><%#Eval("UnitPrice") %></td><td><%#Eval("UnitsInStock") %></td></tr>
</AlternatingItemTemplate>
<ItemTemplate>
<tr><td><%#Eval("ProductID") %></td><td><%#Eval("ProductName") %></td><td><%#Eval("UnitPrice") %></td><td><%#Eval("UnitsInStock") %></td></tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
</form>
</body>
</html>
.cs 代码如下:
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;
using System.IO;
public partial class ajax_xmlHttpRequest_RepeaterDemoResult : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
using (SqlConnection con = new SqlConnection("server=.;uid=sa;pwd=sa;database=Northwind"))
{
SqlDataAdapter sda = new SqlDataAdapter("select * from products", con);
DataSet ds = new DataSet();
int count, pageSize, currentPage;
int.TryParse(Request.Form["pageSize"], out pageSize);
pageSize = pageSize == 0 ? 10 : pageSize;
int.TryParse(Request.Form["count"], out count);
int.TryParse(Request.Form["pageNum"], out currentPage);
int tempCount = count % pageSize == 0 ? count / pageSize : count / pageSize + 1;
if (tempCount < currentPage)
{
currentPage = tempCount;
}
sda.Fill(ds, (currentPage - 1) * pageSize, pageSize, "products");
rp.DataSource = ds.Tables["products"].DefaultView;
rp.DataBind();
Response.Clear();
StringWriter sw = new StringWriter();
HtmlTextWriter htw = new HtmlTextWriter(sw);
rp.RenderControl(htw);
Response.Write(sw.ToString());
Response.End();
}
}
}
程序到这里已经完成了，可以运行看效果了。如果觉得样式简单，可以设置CSS来美观，这里主要是实现功能。
