jQuery getJSON()+.ashx 实现分页(改进版)

时间:2020-05-13 人气:0

参考了：
改进的地方：
1、ashx返回json数据，减少传输数据量，html页面样式控制也比较灵活；
2、改写html页的jQuery代码；
3、把3个ashx文件简化为1个。
一、创建表的测试数据：

create table test(id int identity,title varchar(36))
declare @index int;
set @index = 1;
while(@index < 8888)
begin
insert test(title) values (newid())
set @index = @index + 1
end

二、.html页

复制代码代码如下:

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title></title>
<script type="text/javascript" src="jquery-1.4.2.min.js"></script>
<script type="text/javascript">
$(function() {
Init();
});
function Init() {
$("#Content").html("");
$("#pageIndex").val(0);
$("#pageInfo").append("当前第1页");
$.getJSON("Handler.ashx", { type: 'first' }, function(data) {
$("#Content").append("<tr><th style＝'width:130px'>id</th><th style＝'width:150px'>title</th></tr>");
$.each(data, function(i) {
$("#Content").append("<tr><td>" + data[i].id + "</td><td>" + data[i].title + "</td></tr>");
})
})
}
function Pre() {
var currIndex = Number($("#pageIndex").val()) - 1;
Go('pre', currIndex);
}
function Next() {
var currIndex = Number($("#pageIndex").val()) + 1;
Go('next', currIndex);
}
function Go(type, index) {
$("#Content").html("");
$("#pageInfo").html("");
if (index == 0 || index == -1) { Init(); return; }
$.getJSON("Handler.ashx", { type: type, index: index }, function(data) {
$("#Content").append("<tr><th style＝'width:130px'>id</th><th style＝'width:150px'>title</th></tr>");
$.each(data, function(i) {
$("#Content").append("<tr><td>" + data[i].id + "</td><td>" + data[i].title + "</td></tr>");
})
$("#pageInfo").append("当前第 " + (index + 1) + " 页");
$("#pageIndex").val(index);
});
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div style="width: 100%">
<table id="Content" >
</table>
</div>
<div id="PagePanel" style="margin-left:20px">
<label id="pageInfo"></label>
<a href="#" onclick="Pre()">上一页</a>
<a href="#" onclick="Next()">下一页</a>
</div>
<input type="hidden" value="0" id="pageIndex" />
</form>
</body>
</html>

三、.ashx页

复制代码代码如下:

public class Handler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "text/plain";
StringBuilder tb = new StringBuilder();
DataBase db = new DataBase();
int pageSize = 10;
int pageIndex = 0;
string type = context.Request.Params["type"];
switch (type)
{
case "first":
DataTable dt1 = db.GetDataSet("select top 10 * from test", null).Tables[0];
tb.Append(Common.DataTableToJSON(dt1, true)); //DataTable转为JSON
break;
case "next":
pageIndex = Convert.ToInt32(context.Request.Params["index"]);
DataTable dt2 = db.GetDataSet("select top " + pageSize.ToString() + " * from test where id> (select max(id) from (select top " + (pageSize * pageIndex).ToString() + " id from test) t)", null).Tables[0];
tb.Append(Common.DataTableToJSON(dt2, true));
break;
case "pre":
pageIndex = Convert.ToInt32(context.Request.Params["index"]);
DataTable dt3 = db.GetDataSet("select top " + pageSize.ToString() + " * from test where id> (select max(id) from (select top " + (pageSize * pageIndex).ToString() + " id from test) t)", null).Tables[0];
tb.Append(JSONHelper.DataTableToJSON(dt));
break;
}
context.Response.Write(tb.ToString());
}
public bool IsReusable
{
get
{
return false;
}
}
}

四、效果

--------------------------------------------------------------------------------------------------------------------
备注 (2010-7-10)：
用sql2005 row_number()分页方法，.ashx页面代码可简化为

复制代码代码如下:

public class Handler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
context.Response.ContentType = "text/plain";
DataBase db = new DataBase();
int pageSize = 10;
int pageIndex = 0;
int.TryParse(context.Request.Params["index"], out pageIndex);
string type = context.Request.Params["type"];
string sql = string.Format("select * from ( select row_number() over (order by id) as rowNum,* from test) as t "
+ " where rowNum>{0} and rowNum<={1}", pageIndex * pageSize, (pageIndex+1) * pageSize);
DataTable dt = db.GetDataSet(sql, null).Tables[0];
context.Response.Write(JSONHelper.DataTableToJSON(dt));
}
public bool IsReusable
{
get
{
return false;
}
}
}

备注：
其中JSONHelper.DataTableToJSON(dt)方法为DataTable解析成JSON，见另一篇文章JSONHelper帮助类

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