find control at runtime
<pre><code>    protected void Button1_Click(object sender, EventArgs e)
    {
        FileUpload F = new FileUpload { ID = "FF" };
        PlaceHolder1.Controls.Add(F);

    }

     protected void Button2_Click(object sender, EventArgs e)
    {
        FileUpload FU = (FileUpload)PlaceHolder1.FindControl("FF");
        Label1.Text = Fu.filename;
      }
</code></pre>

<p>so i cant find the fileupload at run time</p>
