用html input控件实现多文件上传

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="UploadFile.aspx.cs" Inherits="Admin_UploadFile" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<HTML>
<HEAD>
    <title>多文件上传</title>
    <script language="JavaScript">
    function addFile()
    {
          var str = '<INPUT type="file" size="50" NAME="File">'
          document.getElementById('MyFile').insertAdjacentHTML("beforeEnd",str)
    }
    </script>
</HEAD>
<body>
    <form id="form1" method="post" runat="server" enctype="multipart/form-data">
      <div align="center">
        <h3>
            文件上传</h3>
        <P id="MyFile"><INPUT type="file" NAME="File" style="width: 431px"></P>
        <P>
          <input type="button" value="增加上传文件" onclick="addFile()" id="Button1"> 
          <asp:Button Runat="server" Text="开始上传" ID="UploadButton" OnClick="UploadButton_Click"></asp:Button>
        </P>
        <P>
        <asp:Label id="strStatus" runat="server" Font-Names="宋体" Font-Bold="True" Font-Size="9pt"
          Width="414px" BorderStyle="None" BorderColor="White"></asp:Label>
        </P>
      </div>
    </form>
</body>
</HTML>

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;

public partial class Admin_UploadFile : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

    }
    protected void UploadButton_Click(object sender, EventArgs e)
    {
        ///'遍历File表单元素
        HttpFileCollection files = HttpContext.Current.Request.Files;

        /// '状态信息
        System.Text.StringBuilder strMsg = new System.Text.StringBuilder();
        strMsg.Append("上传的文件分别是：<hr color=red>");
        try
        {
            for (int iFile = 0; iFile < files.Count; iFile++)
            {
                ///'检查文件扩展名字
                HttpPostedFile postedFile = files[iFile];
                string fileName, fileExtension;
                fileName = GetCreate()+ GetRandomint()+iFile.ToString();
                //fileName =fileName+System.IO.Path.GetFileName(postedFile.FileName);
                fileName = fileName + System.IO.Path.GetExtension(postedFile.FileName);
                if (fileName != "")
                {
                    fileExtension = System.IO.Path.GetExtension(fileName);
                    strMsg.Append("上传的文件类型：" + postedFile.ContentType.ToString() + "<br>");
                    strMsg.Append("客户端文件地址：" + postedFile.FileName + "<br>");
                    strMsg.Append("上传文件的文件名：" + fileName + "<br>");
                    strMsg.Append("上传文件的扩展名：" + fileExtension + "<br><hr>");
                    ///'可根据扩展名字的不同保存到不同的文件夹
                    ///注意：可能要修改你的文件夹的匿名写入权限。
                    postedFile.SaveAs(System.Web.HttpContext.Current.Request.MapPath("Upload/") + fileName);
                }
            }
            strStatus.Text = strMsg.ToString();
            // return true;
        }
        catch (System.Exception Ex)
        {
            strStatus.Text = Ex.Message;
            // return false;
        }

}

    //随机数函数（大于10000）
    private string GetRandomint()
    {
        Random random = new Random();
        return (random.Next(10000)).ToString();

    }

    //时间
    public string GetCreate()
    {
        string datetime = System.DateTime.Now.ToShortDateString();
        return datetime;

}
}

可是当我把它做成usercontrol，却不能用了，I don't know !!!
next ,i will use upload control to .....