ListView Control에서 Panel 감추기 혹은 보이기

<asp:ListView runat="server" ID="lv" OnItemCommand="lv_ItemCommand">
        <LayoutTemplate>
            <asp:PlaceHolder ID="itemPlaceholder" runat="server" />
        </LayoutTemplate>
        <ItemTemplate>
            <%# Eval("title") %>
           
            <asp:LinkButton runat="server" ID="btn" CommandName="s">[test]</asp:LinkButton>
            <asp:Panel runat="server" ID="pnl">패널</asp:Panel>
           
            <br />
        </ItemTemplate>
    </asp:ListView>

protected void lv_ItemCommand(object sender, ListViewCommandEventArgs e)
        {
            if (e.CommandName.Equals("s"))
            {
                Panel p = (Panel)e.Item.FindControl("pnl");

                p.Visible = !p.Visible;            
            } 
        }