通过ajax异步减少网络内容传输，而json则可以把传输内容缩减到纯数据；然后利用jquery内置的ajax功能直接获得json格式的数据；在客户端直接绑定到数据控件里面，从而达到最优。
1.设计htm页面
<!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> <title>test2</title> <script language="javascript" type="text/javascript" src="js/jquery-latest.pack.js"></script> <script language="javascript" type="text/javascript" src="js/PageDate.js"></script> </head> <body> <div> <div> <br /> <input id="first" type="button" value=" << " /><input id="previous" type="button" value=" < " /><input id="next" type="button" value=" > " /><input id="last" type="button" value=" >> " /> <span id="pageinfo"></span> <ul id="datas"> <li id="template"> <span id="OrderID"> 订单ID </span>/ <span id="CustomerID"> 客户ID </span> <span id="EmployeeID"> 雇员ID </span>/ <span id="OrderDate"> 订购日期 </span>/ <span id="ShippedDate"> 发货日期 </span>/ <span id="ShippedName"> 货主名称 </span>/ <span id="ShippedAddress"> 货主地址 </span>/ <span id="ShippedCity"> 货主城市 </span>/ <span id="more"> 更多信息 </span> </li> </ul> </div> <div id="load" style="left: 0px; position: absolute; top: 0px; background-color: red"> LOADING.... </div> <input type="hidden" id="pagecount" /> </div> </body> </html> ////注：ID属性比较重要，用于数据绑定。
2.使用jQuery编写AJAX请求文件
var pageIndex = 1
var pageCount = 0;
$(function() {
GetPageCount(); //取得分页总数
pageCount = parseInt($("#pagecount").val()); //分页总数放到变量pageCount里
$("#load").hide(); //隐藏loading提示
$("#template").hide(); //隐藏模板
ChangeState(0, 1); //设置翻页按钮的初始状态
bind(); //绑定第一页的数据
//第一页按钮click事件
$("#first").click(function() {
pageIndex = 1;
ChangeState(0, 1);
bind();
});
//上一页按钮click事件
$("#previous").click(function() {
pageIndex -= 1;
ChangeState( - 1, 1);
if (pageIndex <= 1) {
pageIndex = 1;
ChangeState(0, -1);
}
bind();
});
//下一页按钮click事件
$("#next").click(function() {
pageIndex += 1;
ChangeState(1, -1);
if (pageIndex >= pageCount) {
pageIndex = pageCount;
ChangeState( - 1, 0);
}
bind(pageIndex);
});
//最后一页按钮click事件
$("#last").click(function() {
pageIndex = pageCount;
ChangeState(1, 0);
bind(pageIndex);
});
});
//AJAX方法取得数据并显示到页面上
function bind() {
$("[@id=ready]").remove();
$("#load").show();
$.ajax({
type: "get",
//使用get方法访问后台
dataType: "json",
//返回json格式的数据
url: "Handler.ashx",
//要访问的后台地址
data: "pageIndex=" + pageIndex,
//要发送的数据
complete: function() {
$("#load").hide();
},
//AJAX请求完成时隐藏loading提示
success: function(msg) { //msg为返回的数据，在这里做数据绑定
var data = msg.table;
$.each(data,
function(i, n) {
var row = $("#template").clone();
row.find("#OrderID").text(n.OrderID);
row.find("#CustomerID").text(n.CustomerID);
row.find("#EmployeeID").text(n.EmployeeID);
row.find("#OrderDate").text(ChangeDate(n.OrderDate));
if (n.RequiredDate !== undefined) row.find("#ShippedDate").text(ChangeDate(n.RequiredDate));
row.find("#ShippedName").text(n.ShipName);
row.find("#ShippedAddress").text(n.ShipAddress);
row.find("#ShippedCity").text(n.ShipCity);
row.find("#more").html("<a href=OrderInfo.aspx?id=" + n.OrderID + "&pageindex=" + pageIndex + "> More</a>");
row.attr("id", "ready"); //改变绑定好数据的行的id
row.appendTo("#datas"); //添加到模板的容器中
});
$("[@id=ready]").show();
SetPageInfo();
}
});
}
function ChangeDate(date) {
return date.replace("-", "/").replace("-", "/");
}
//设置第几页/共几页的信息
function SetPageInfo() {
$("#pageinfo").html(pageIndex + "/" + pageCount);
}
//AJAX方法取得分页总数
function GetPageCount() {
$.ajax({
type: "get",
dataType: "text",
url: "Handler.ashx",
data: "getPageCount=1",
async: false,
success: function(msg) {
$("#pagecount").val(msg);
}
});
}
//改变翻页按钮状态
function ChangeState(state1, state2) {
if (state1 == 1) {
document.getElementById("first").disabled = "";
document.getElementById("previous").disabled = "";
} else if (state1 == 0) {
document.getElementById("first").disabled = "disabled";
document.getElementById("previous").disabled = "disabled";
}
if (state2 == 1) {
document.getElementById("next").disabled = "";
document.getElementById("last").disabled = "";
} else if (state2 == 0) {
document.getElementById("next").disabled = "disabled";
document.getElementById("last").disabled = "disabled";
}
}
3.利用JSON三方控件在服务器端获取JSON格式数据
<%@ WebHandler Language="C#" Class="jQueryJSON.Handler" %>
using System;
using System.Data;
using System.Web;
using System.Collections;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Configuration;
using System.Data.SqlClient;
using System.Text;
using System.Xml;
using NetServ.Net.Json;
namespace jQueryJSON
{
/// <summary>
/// $codebehindclassname$ 的摘要说明
/// </summary>
[WebService(Namespace = "http://tempuri.org/json/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
public class Handler : IHttpHandler
{
readonly int PageSize = int.Parse(ConfigurationManager.AppSettings["PageSize"]);
public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "text/plain";
//不让浏览器缓存
context.Response.Buffer = true;
context.Response.ExpiresAbsolute = DateTime.Now.AddDays(-1);
context.Response.AddHeader("pragma", "no-cache");
context.Response.AddHeader("cache-control", "");
context.Response.CacheControl = "no-cache";
string result = "";
if (context.Request.Params["getPageCount"] != null) result = GetPageCount();
if (context.Request.Params["pageIndex"] != null)
{
string pageindex = context.Request.Params["pageIndex"];
result = GetPageData(context.Request.Params["pageIndex"]);
}
context.Response.Write(result);
}
private string GetPageData(string p)
{
int PageIndex = int.Parse(p);
string sql;
if (PageIndex == 1)
sql = "select top " + PageSize.ToString() + " * from Orders order by OrderID desc";
else
sql = "select top " + PageSize.ToString() + " * from Orders where OrderID not in(select top " + ((PageIndex - 1) * PageSize).ToString() + " OrderID from Orders order by OrderID desc) order by OrderID desc";
string dbfile = ConfigurationManager.ConnectionStrings["conn"].ToString();
SqlConnection conn = new SqlConnection(dbfile);
SqlDataAdapter da = new SqlDataAdapter(sql, conn);
DataTable dt = new DataTable("table");
da.Fill(dt);
return DataTableJson(dt);
}
private string GetPageCount()
{
string dbfile = ConfigurationManager.ConnectionStrings["conn"].ToString();
SqlConnection conn = new SqlConnection(dbfile);
SqlCommand cmd = new SqlCommand("select count(*) from Orders", conn);
conn.Open();
int rowcount = Convert.ToInt32(cmd.ExecuteScalar());
conn.Close();
return ((rowcount + PageSize - 1) / PageSize).ToString();
}
private string DataTable2Json(DataTable dt)
{
StringBuilder jsonBuilder = new StringBuilder();
jsonBuilder.Append("{\"");
jsonBuilder.Append(dt.TableName);
jsonBuilder.Append("\":[");
for (int i = 0; i < dt.Rows.Count; i++)
{
jsonBuilder.Append("{");
for (int j = 0; j < dt.Columns.Count; j++)
{
jsonBuilder.Append("\"");
jsonBuilder.Append(dt.Columns[j].ColumnName);
jsonBuilder.Append("\":\"");
jsonBuilder.Append(dt.Rows[i][j].ToString());
jsonBuilder.Append("\",");
}
jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
jsonBuilder.Append("},");
}
jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
jsonBuilder.Append("]");
jsonBuilder.Append("}");
return jsonBuilder.ToString();
}
private string DataTableJson(DataTable dt)
{
JsonWriter writer = new JsonWriter();
JsonObject content = new JsonObject();
JsonArray Orders = new JsonArray();
JsonObject Order;
JsonObject OrderItem = new JsonObject();
for (int i = 0; i < dt.Rows.Count; i++)
{
Order = new JsonObject();
for(int j =0;j<dt.Columns.Count;j++)
{
Order.Add(dt.Columns[j].ColumnName, dt.Rows[i][j].ToString());
}
Orders.Add(Order);
}
content.Add(dt.TableName, Orders);
content.Write(writer);
writer = new IndentedJsonWriter();
content.Write(writer);
return writer.ToString();
}
public bool IsReusable
{
get
{
return false;
}
}
}
}
以上是jquery ajax json 综合应用实例。
