jquery ajax json 综合应用实例

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

<code class="html"> 
 
 
<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> 
  
 
 
<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> 
 
 
////注：ID属性比较重要，用于数据绑定。</code>

 

2.使用jQuery编写AJAX请求文件

<code class="javascript">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 = 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=%22" n.orderid 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";
    }
}</code>

 

3.利用JSON三方控件在服务器端获取JSON格式数据 

<code class="cs"> 
  
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 </code>

以上是jquery ajax json 综合应用实例。