在asp.net下如何在aspx.cs后台代码里获取用客户端脚本语言改写aspx的页面控件元素？例如：添加一<select>控件，并标记为服务端运行，初始时有一选项，当在页面使用JavaScript增加、删除新项时，点击一Button触发后台事件，在aspx.cs下怎样才能获取到在页面的修改的元素？和页面回发再次展现时，怎样才能使刚刚新修改的元素保持在页面上啊？谢谢！期待解答！
aspx代码如下：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebTestJSSelectDemo.aspx.cs" Inherits="CT.WebSearchFiles.WebTestJSSelectDemo" %>
<!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 runat="server">
<title>select options 增加、删除操作Demo</title>
<script language="javascript" type="text/javascript">
//添加的一项
function AddOption()
{
var option = new Option("新项目");//new Option("新项目","1");
var item = document.getElementById("select1").options.length;
document.getElementById("select1").options[item] = option;
document.getElementById("select1").selectedIndex = item;
alert("添加成功！");
}
//在选中的一项后添加一项
function AddSelectedOption()
{
var option = new Option("新项目");//new Option("新项目","1");
var item = document.getElementById("select1").selectedIndex+1;
if(item != "undefined" && item != -1)
{
document.getElementById("select1").options[item] = option;
document.getElementById("select1").selectedIndex = item;
alert("添加成功！");
}
else
{
alert("请选择一项！");
}
}
//删除选中的一项
function DelOption()
{
var item = document.getElementById("select1").selectedIndex;
//document.form1.select1.selectedIndex;
if(item != "undefined" && item != -1)
{
document.getElementById("select1").options[item] = null;
document.getElementById("select1").selectedIndex = item - 1;
alert("删除一项成功！");
}
else
{
alert("请选择一项！");
}
}
//删除除第一项之后的所有项
function DelAllOption()
{
var num = document.getElementById("select1").options.length;
for(var i=num ; i>= 1;i--)
{
document.getElementById("select1").options[i] = null;
}
alert("成功删除成功！");
}
</script>
</head>
<body>
<form id="form1" runat="server">
<select id="select1" name="select1" size="10" runat="server">
<option value="0">选择项目</option>
</select>
<input type="button" onclick="AddOption()" value="添加项目" >
<input type="button" onclick="AddSelectedOption()" value="在选中后添加项目" >
<input type="button" onclick="DelOption()" value="删除项目" >
<input type="button" onclick="DelAllOption()" value="删除全部" >
<br />
<br />
<br />
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
</form>
</body>
</html>
aspx.cs后台代码如下：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
namespace CT.WebSearchFiles
{
public partial class WebTestJSSelectDemo : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
//客户端添加删除的项这里看不到 须研究解决
string strCount = this.select1.Items.Count.ToString();
string[] strKeys = Request.Params.AllKeys;
//这样也只能获取到最后一个新项目，其余的获取不到
string[] strValues = Request.Params.GetValues("select1");
}
}
}
