DataGrid功能強大，我們只用寫幾行代碼就能夠實現複雜的頁面數據顯示。數據多的時候免不了要分頁顯示，DataGrdi本身自帶分頁功能，但是當數據量少的時候很方便，當大數據量時，DataGrid得分頁機制就不太好了。於是在網上找到了一種比較好的利用存儲過程實現分頁機制(客戶端想要第幾頁就取第幾頁數據，上十萬級的數據查詢也很快，數據量再多的時候就沒試過了，等有時間把利用存儲過程分頁也寫在blog上)在工作中爲了讓客戶用的更舒服點，也趕時髦，想利用Ajax來實現DataGrid無刷新分頁。主要用RenderControl方法把DataGrid翻譯成Html代碼，然後用Web Service 返回。當然也可以用別的方法。
GenericAjaxWS.asmx.cs
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Diagnostics;
using System.Web;
using System.Web.Services;
using System.Configuration;
using System.Web.UI.WebControls;
using System.Web.UI;
using System.IO;
namespace GenricAjaxWS
{
[WebService(Namespace="http://localhost/GenricAjaxWS/")]
public class GenricAjaxWS : System.Web.Services.WebService
{
SqlConnection con;
SqlDataAdapter da;
SqlCommand cmd;
DataSet ds;
public GenricAjaxWS()
{
InitializeComponent();
con= new SqlConnection(ConfigurationSettings.AppSettings["Connect"]);
da=new SqlDataAdapter("",con);
cmd=new SqlCommand("",con);
ds=new DataSet("TahaSchema");
}
#region Component Designer generated code
//Required by the Web Services Designer
private IContainer components = null;
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
}
/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if(disposing && components != null)
{
components.Dispose();
}
base.Dispose(disposing);
}
#endregion
/// <summary>
/// this function accepts TSql statment and returns dataset
/// </summary>
[WebMethod]
public string getGrid(string sqlStr,int pageIndex)
{
da.SelectCommand.CommandText=sqlStr;
da=new SqlDataAdapter(sqlStr,con);
da.Fill(ds,"myTable");
DataGrid dataGrid = new DataGrid();
dataGrid.AutoGenerateColumns = true;
dataGrid.DataSource = ds.Tables["myTable"].DefaultView;
dataGrid.AllowPaging = true;
dataGrid.PageSize = 4;
dataGrid.PagerStyle.Visible = false;
dataGrid.CurrentPageIndex = pageIndex;
try
{
dataGrid.DataBind();
}
catch(Exception)
{
}
StringWriter wr = new StringWriter();
HtmlTextWriter writer = new HtmlTextWriter(wr);
dataGrid.RenderControl(writer);
string gridHtml = wr.ToString();
wr.Close();
writer.Close();
DropDownList ddl_Pager = new DropDownList();
ddl_Pager.Attributes.Add("onchange","goToPage(this.value)");
string pager="";
for(int i=0;i<dataGrid.PageCount;i++)
{
ListItem lItem = new ListItem(i.ToString(),i.ToString());
ddl_Pager.Items.Add(lItem);
if(i==pageIndex)
{
pager += "[background-color:#ffdd11;width" +
":20px;align:center/"><a href=/"#/" onclick" +
"=/"goToPage('"+i+"')/">"+i+"</a>]";
}
else
{
pager += "[width:20px;align:center/">" +
"<a href=/"#/" οnclick=/"goToPage" +
"('"+i+"')/" >"+i+"</a>]";
}
}
ddl_Pager.SelectedIndex = pageIndex;
wr = new StringWriter();
writer = new HtmlTextWriter(wr);
ddl_Pager.RenderControl(writer);
string pagerHtml = "<input type='button'" +
" value='<' οnclick='goToPrevPage()'>";
pagerHtml += wr.ToString();
pagerHtml += "<input type='button' value='>'" +
" οnclick='this.disabled=goToNextPage()'>";
wr.Close();
writer.Close();
return pager+pagerHtml+"<br>"+gridHtml;
}
}
}
上面的是Web服務，然後利用Ajax請求這個服務來獲取要現實的數據。以下是客戶端JavaScript代碼：
AjaxFuncs.js
//聲明異步請求對象
/////////////////////////////////////////////////////////////////
var xmlhttp;
/////////////////////////////////////////////////////////////////
//填充DataGrid,這個函數有3個參數。
//第一個是包含DataGrid的DIV的ID
//第二個是查詢數據的sql語句
//第三個是要獲取第幾頁數據
/////////////////////////////////////////////////////////////////
var ph;
var fillGrid_Str_SQL="";
var currentPageIndex ;
function fillGrid(myPH,str_Sql,pageIndex){
ph = window.document.getElementById(myPH);
fillGrid_Str_SQL = str_Sql;
currentPageIndex = pageIndex;
var url = "http://localhost/GenricAjaxWS/GenricAjaxWS" +
".asmx/getGrid?sqlStr="+str_Sql+
"&pageIndex="+pageIndex;
if(window.XMLHttpRequest)
{
xmlhttp=new XMLHttpRequest();
xmlhttp.onreadystatechange=fillGrid_Change;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}
//code for IE
else if (window.ActiveXObject)
{
try
{
xmlhttp= new ActiveXObject("Msxml2.XMLHTTP");
}
catch(e)
{
try
{
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
catch(e){}
}
if(xmlhttp)
{
try
{
xmlhttp.onreadystatechange=fillGrid_Change;
xmlhttp.open("GET",url,false);
xmlhttp.send();
}
catch(e){}
}
}
}
function fillGrid_Change()
{
if(xmlhttp.readyState==4&&xmlhttp.status==200)
{
//var rows=xmlhttp.responseXML.
// selectNodes(".//TahaSchema//TahaTable");
var row = xmlhttp.responseXML.selectNodes(".//");
ph.innerHTML = row[1].text;
}
}
function goToPage(pageIndex){
fillGrid(ph.id,fillGrid_Str_SQL,pageIndex)
}
function goToNextPage(){
try{
fillGrid(ph.id,fillGrid_Str_SQL,
parseInt(currentPageIndex)+1);
return false;
}
catch(e){
return true;
}
}
function goToPrevPage(){
fillGrid(ph.id,fillGrid_Str_SQL,
parseInt(currentPageIndex)-1)
}
最後就是顯示數據的html頁面，實例代碼如下：
AjaxGrid.html：
<html>
<head>
<title>AjaxGrid</title>
<script language="javascript"
type="text/javascript" src="ajaxFuncs.js"></script>
</head>
<body οnlοad="fillGrid('myPH','select * from sales',1)">
<form id="Form1" method="post" runat="server">
<div id="myPH" ></div>
</form>
</body>
</html>
到此利用Ajax實現DataGrid無刷新分頁就完成了。