creating multiple asyncFileUpload dynamically

I have a asp .net web form where I am using Ajax asyncFileUpload1, so that when I browse an image it triggers a function and uploads the file.

Now when the file gets uploaded I want to create another asyncFileUpload2 on the same page. But it's not working.

This works

<div id="divform" runat="server">        
</div>

<div id="divform2" runat="server">      
</div>

<asp:Button ID="btnAddFileUpload" runat="server" Text="add" Visible="false" OnClick="btnAddFileUpload_Click" />

 **On Backend server side:**


 protected void btnAddFileUpload_Click(object sender, EventArgs e)
    {
        AsyncFileUpload AsyncFileUpload1 = new AsyncFileUpload();
        AsyncFileUpload1.UploadedComplete += new EventHandler<AsyncFileUploadEventArgs>(AsyncFileUpload1_UploadedComplete);
        divform.Controls.Add(AsyncFileUpload1);

        AsyncFileUpload AsyncFileUpload2 = new AsyncFileUpload();
        AsyncFileUpload2.UploadedComplete += new EventHandler<AsyncFileUploadEventArgs>(AsyncFileUpload2_UploadedComplete);
        divform2.Controls.Add(AsyncFileUpload2);
    }

But I don't want in this way, so I removed Add button and on page load, I dynamically created first AsyncFilepUpload1 button. that worked. And once I browse a file, after it's upload another AsyncFileUpload2 should be created. But file gets uploaded without creating the fileUpload2 button and code does not throw any error.

This doesn't work

<div id="divform" runat="server">        
</div>

<div id="divform2" runat="server">      
</div>

**On backend server side**

protected void Page_Load(object sender, EventArgs e)
    {
        
        AsyncFileUpload AsyncFileUpload1 = new AsyncFileUpload();
        AsyncFileUpload1.UploadedComplete += new EventHandler<AsyncFileUploadEventArgs>(AsyncFileUpload1_UploadedComplete);
        divform.Controls.Add(AsyncFileUpload1);
    }

void AsyncFileUpload1_UploadedComplete(object sender, AsyncFileUploadEventArgs e)
    {            
        string filename = System.IO.Path.GetFileName(e.FileName);
        string savePath = MapPath("Upload/" + filename + DateTime.Now.ToString("MM_dd_yyyy_HH_mm"));            
        ((AsyncFileUpload)sender).SaveAs(savePath);

        AsyncFileUpload AsyncFileUpload2 = new AsyncFileUpload();
        AsyncFileUpload2.UploadedComplete += new EventHandler<AsyncFileUploadEventArgs>(AsyncFileUpload2_UploadedComplete);
        divform2.Controls.Add(AsyncFileUpload2);
    }