jquery与json的结合

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=" >> " /> 
&nbsp;<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+">&nbsp;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"];  
//if (context.Cache.Get(pageindex) != null)  
// result = context.Cache.Get(pageindex).ToString();  
//else  
//{  
// result = GetPageData(context.Request.Params["pageIndex"]);  
// context.Cache.Add(  
// pageindex,  
// result,  
// null,  
// DateTime.Now.AddMinutes(1),  
// System.Web.Caching.Cache.NoSlidingExpiration,  
// System.Web.Caching.CacheItemPriority.Default,  
// null);  
//}  
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;  
}  
}  
}  
} 
编程技巧