fileupload

Question

hi all

here my code

 <asp:UpdatePanel ID="UpdatePanel1" runat="server"> 
 
       <ContentTemplate> 
        
           <asp:Button ID="Button2" runat="server" Text="Button" onclick="Button2_Click" /> 
           <asp:Panel ID="Panel1" runat="server" Visible="false"> 
        <asp:FileUpload ID="FileUpload1" runat="server" />    
           </asp:Panel> 
         
         
       </ContentTemplate> 
        </asp:UpdatePanel> 
             <asp:LinkButton ID="LinkButton1" runat="server" onclick="LinkButton1_Click">LinkButton</asp:LinkButton

protected void LinkButton1_Click(object sender, EventArgs e) 
        { 
            if (FileUpload1.HasFile) 
            {                 } 
        } 
 
        protected void Button2_Click(object sender, EventArgs e) 
        { 
            Panel1.Visible = true; 
        }

fileupload is working when without asp panel. my question is when i put a asp panel it doesnt work. i handle panel visible from code behind

thanks