PageBase class in not hiding button control in run time

Question

Dear Friend,

I am facing one strange behavior in my ASP.net (Web Form) web application. I have created one PageBase class (PageBase.cs) and I am implementing this in my all web 

page (code behind class). Actually I am hiding/showing a particular button control in each page based on some condition so implemented that logic in PageBase class on 

"OnPreRender" event. I am recurssively searching that button in each page and performing action. This functionality is working perfectly when I run application through 

code but same functionality stops working after deployment on web site (under IIS). I am not sure why this behavior is happenning. My sample code is below. Could you 

please tell me what could be possibility. Thanks for your support in advance.

PageBase.cs

===========

public class PageBase : System.Web.UI.Page

{

        protected override void OnPreRender(EventArgs e)

        {

               base.OnPreRender(e);

               Page page = (Page)HttpContext.Current.Handler;

               ShowHideControl(Page.Controls);

        }

        private void ShowHideControl(ControlCollection page)

        {

                foreach (Control ctrl in page)

                {

                      //If current control is AddNew button

                      if (ctrl.ID == "btnAddNew")

                      {

                             //Hide button if add permission is not given

                             if (isAdd==false)

                             { 

                                        ctrl.Visible = false;

                              }

                      }

                      if (ctrl.HasControls())

                      {

                             ShowHideControl(ctrl.Controls);

                      }

                }

         }

}

BusinessMaster.aspx.c

===============

public partial class BusinessMaster : PageBase 

BusinessMaster.aspx

=============

<table style="width: 100%">

<tr>

<td align="right">

</td>

<td height="35" align="right" style="width: 50%">

<asp:Button ID="btnAddNew" runat="server" Text="Add New" CssClass="FormBtnSmall" OnClick="btnAddNew_Click" TabIndex="8" />

</td>

</tr>

</table>