像google,QQ,163那样一次上传多个文件(downmoon)

<form id="frmUpload" runat="server" enctype="multipart/form-data">
    <div>
     <table width="100%" border="0px" cellpadding="0px" cellspacing="2">
                    <tr height="80">
                        <td align="right" bgcolor="#EAEAEA">
                            上传图片：</td>
                        <td bgcolor="#f7f7f7" valign="top">
                            <table cellspacing="0" cellpadding="0" width="100%" align="left" border="0">
                                <tr height="30">
                                    <td class="tab_font_left" align="left" width="100%">
                                        <div>
                                            <table width="100%" border="0" cellpadding="2" cellspacing="1" id="SignFrame">
                                                <tr id="trHeader" align="center">
                                                    <td width="60" height="25px;" align="center" bgcolor="#1C5E55" style="color: #FFFFFF" mce_style="color: #FFFFFF">
                                                        序号</td>
                                                    <td bgcolor="#1C5E55" align="center" style="color: #FFFFFF" mce_style="color: #FFFFFF">
                                                        上传文件</td>
                                                </tr>
                                            </table>
                                        </div>
                                        <div>
                                            <input type='file' style="display: none;" mce_style="display: none;" size='50' id="file1" runat="server" />
                                             <input type="button" name="Submit" value="添加上传文件" onclick="AddSignRow()" />
                                             
                                            <input type="button" name="Submit2" value="清空" onclick="ClearAllSign()" />
                                            <input name='txtTRLastIndex' type='hidden' id='txtTRLastIndex' value="1" />
                                            <br />
                                            <span class="notetext">注：最多只能上传三个图片，如果需要更新，请先删除原图片</span>
                                        </div>
                                    </td>
                                </tr>
                            </table>
                        </td>
                    </tr>
                </table>
    </div>
    <div>
    <table width="100%" border="0" cellpadding="0" cellspacing="0" align="center">
    <tr height="30">
        <td align="center" colspan="2" bgcolor="#f7f7f7">
            <asp:Button ID="btnInsert" Text="确认添加" runat="server" OnClick="btnInsert_Click" />  <asp:Button ID="btnBack" Text="放弃返回" runat="server" />
        </td>
    </tr>
</table>
    </div>
    
    </form>

<mce:script type="text/javascript" language="javascript"><!--
var TempCount=1;//不可删除！downmoon 20071025
    // Example: obj = findObj("image1");
    function findObj(theObj, theDoc)
    {
          var p, i, foundObj;
          if(!theDoc) theDoc = document;
          if( (p = theObj.indexOf("?")) > 0 && parent.frames.length)
          {
            theDoc = parent.frames[theObj.substring(p+1)].document;
            theObj = theObj.substring(0,p);
          }
          if(!(foundObj = theDoc[theObj]) && theDoc.all) foundObj = theDoc.all[theObj];
          for (i=0; !foundObj && i < theDoc.forms.length; i++)
            foundObj = theDoc.forms[i][theObj];
          for(i=0; !foundObj && theDoc.layers && i < theDoc.layers.length; i++)
            foundObj = findObj(theObj,theDoc.layers[i].document);
          if(!foundObj && document.getElementById) foundObj = document.getElementById(theObj);
         
          return foundObj;
    }
    function AddSignRow()
    {
                if(TempCount>3) return;
                 var txtTRLastIndex = findObj("txtTRLastIndex",document);
                 var rowID = parseInt(txtTRLastIndex.value);
                 var signFrame = findObj("SignFrame",document);
                 var newTR = signFrame.insertRow(signFrame.rows.length);
                 newTR.id = "SignItem" + rowID;
                 var newNameTD=newTR.insertCell(0);
                 newNameTD.innerHTML = newTR.rowIndex.toString();
                 var newNameTD=newTR.insertCell(1);
                  newNameTD.innerHTML = "<input name='MyFile" + rowID + "' id='MyFile" + rowID + "' type='file' size='50' />";
                 txtTRLastIndex.value = (rowID + 1).toString() ;
                 TempCount=TempCount+1;
    }
    function DeleteSignRow(rowid)
    {
         var signFrame = findObj("SignFrame",document);
         var signItem = findObj(rowid,document);
         var rowIndex = signItem.rowIndex;
         signFrame.deleteRow(rowIndex);
         for(i=rowIndex;i<signFrame.rows.length;i++){
          signFrame.rows[i].cells[0].innerHTML = i.toString();
         }
    }
    function ClearAllSign()
    {
         if(confirm('确定要清空所有上传的文件吗？')){
          var signFrame = findObj("SignFrame",document);
          var rowscount = signFrame.rows.length;
          for(i=rowscount - 1;i > 0; i--){
           signFrame.deleteRow(i);
          }
          var txtTRLastIndex = findObj("txtTRLastIndex",document);
          txtTRLastIndex.value = "1";
          TempCount=1;
          AddSignRow();
         }
    }
// --></mce:script>

protected void btnInsert_Click(object sender, EventArgs e)
    {
         HttpFileCollection files = HttpContext.Current.Request.Files;
        for (int iFile = 1; iFile  < = Request .Files.Count; iFile++)
        {    ///'检查文件扩展名字
            HttpPostedFile postedFile  = files[iFile  - 1];
            if (postedFile ! = null  && postedFile.ContentLength  >  0)
            {
                //UploadFile
            }
        }
    }