如何使用动态生成的上传控件

我在页面动态生成了一个上传控件
   现在我想上传图片或flash
     但是现在获得不到页面上的控件（动态生成的控件在页面上不显示）
      所以无法上传
         现在不知道该怎么做
请各位多多指教

解决方案 »

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protected void Page_Load(object sender, EventArgs e)
{
    Button btn = new Button();
    btn.ID = "btn_bank_submit";
    btn.Text = "网上支付";
    btn.Click += new EventHandler(btn_bank_submit_Click);
    this.Controls.Add(btn);
}类似这样。
上传控件用JS生成<!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></title>
<style type="text/css">

</style>
<script type="text/javascript" src="../js/jquery-1.4.js"></script>
<script type="text/javascript">
var i=1;
function add(){
document.getElementById("list").innerHTML+="<li class=\"li\"><input type=\"file\" name=\"imgFile"+i+"\" /><a href=\"javascript:add();\">+</a><a href=\"javascript:del();\">-</a></li>";
i+=1;
}
function del(){
$(".li:first").detach();
}
</script>
</head>
<body>
<div id="upload">
<form action="../ashx/upload.ashx" method="post"  enctype="multipart/form-data">
    <ul id="list">
      <li><input type="file" name="imgfile" /><a href="javascript:add();">+</a></li>
    </ul>
    <div>
      <input type="submit" value="上传" onclick="javascript:document.getElementById('upload').style.display='none'; document.getElementById('loading').style.display='block';" />
    </div>
</form>
</div>
<div id="loading" style="display:none;">文件上传中……</div>
</body>
</html>
using System;
using System.Collections.Generic;
using System.Web;
using System.IO;
using System.Globalization;
using System.Collections;namespace Web.asp_bin.admin.ashx
{
    /// <summary>
    /// $codebehindclassname$ 的摘要说明
    /// </summary>
    public class upload : IHttpHandler
    {
        //文件保存目录路径
        private String savePath = "/upload/images/" + DateTime.Now.ToString("yyyy") + DateTime.Now.ToString("MM") + "/";
        //文件保存目录URL
        private String saveUrl = "/upload/images/" + DateTime.Now.ToString("yyyy") + DateTime.Now.ToString("MM") + "/";        //定义允许上传的文件扩展名
        private String fileTypes = new Alvin.BLL.Setting().AttachmentType; //从网站设置中读取可以上传的类型//System.Configuration.ConfigurationManager.AppSettings["fileTypes"];
        //最大文件大小
        private int maxSize = int.Parse(System.Configuration.ConfigurationManager.AppSettings["maxSize"]) * 1024;
        private HttpContext context;
        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            this.context = context;
            string strID=context.Request.QueryString["ID"];//返回的控件ID
            string path = context.Request.QueryString["Path"];
            if (!string.IsNullOrEmpty(path))
            {
                if(System.IO.Directory.Exists(context.Server.MapPath(path)))
                {
                    savePath=path;
                    saveUrl=path;
                }
            }
            //HttpPostedFile imgFile = context.Request.Files[0];
            string retPath = string.Empty;
            for (int i=0; i<context.Request.Files.Count;i++)
            {
                HttpPostedFile imgFile = context.Request.Files[i];
                if (imgFile == null)
                {
                    context.Response.Write("请选择文件。");
                    return;
                }                String dirPath = context.Server.MapPath(savePath);
                if (!Directory.Exists(dirPath))
                {
                    Directory.CreateDirectory(dirPath);//如果不存在该文件夹，则创建文件夹
                }                String fileName = imgFile.FileName;
                String fileExt = Path.GetExtension(fileName).ToLower();
                ArrayList fileTypeList = ArrayList.Adapter(fileTypes.Split(','));                if (imgFile.InputStream == null || imgFile.InputStream.Length > maxSize)
                {
                    context.Response.Write("<span style=\"margin: 0px;padding: 0px;font-size: 12px;\">上传文件大小超过限制。<a href=../inc/upload.aspx?ID=" + strID + ">点击重新选择上传</a></span>");
                    return;
                }                if (String.IsNullOrEmpty(fileExt) || Array.IndexOf(fileTypes.Split(','), fileExt.Substring(1).ToLower()) == -1)
                {
                    context.Response.Write("<span style=\"margin: 0px;padding: 0px;font-size: 12px;\">上传文件扩展名是不允许的扩展名。<a href=../inc/upload.aspx?ID=" + strID + ">点击重新选择上传</a></span>");
                    return;
                }                String newFileName = DateTime.Now.ToString("yyyyMMddHHmmss_ffff", DateTimeFormatInfo.InvariantInfo) + i + fileExt;
                String filePath = dirPath + newFileName;

                imgFile.SaveAs(filePath);
                String fileUrl = saveUrl + newFileName;
                retPath += fileUrl + ",";
            }
            retPath = retPath.Substring(0, retPath.Length - 1);
            if (string.IsNullOrEmpty(strID))
            {
                context.Response.Write("<span style=\"margin: 0px;padding: 0px;font-size: 12px;\">上传成功！<a href=" + context.Request.UrlReferrer.ToString() + ">我还要上传</a></sapn>");
            }
            else
            {
                context.Response.Write("<script type=\"text/javascript\"> parent.document.getElementById(\"" + strID + "\").value=\"" + retPath + "\";</script><span style=\"margin: 0px;padding: 0px;font-size: 12px;\">上传成功！<a href=" + context.Request.UrlReferrer.ToString() + ">点击重新上传</a></sapn>");
            }
        }        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}