Removing/Hiding asp control from aspx page using web.config

System.Web.UI.HtmlControls.HtmlGenericControl DropDownList=
                             this.Master.FindControl("dropdownlistID") as 
                             System.Web.UI.HtmlControls.HtmlGenericControl;
     this.Master.Controls.Remove(DropDownList);

Here what I did and it's very useful
In web.config add this

<configuration>
  <appSettings>
    <!-- Dynamic Drop down list keys-->
    <add key="Default.aspx" value="true"/>
    <add key="HomeLHA.aspx" value="true"/>
    <add key="Analytics.aspx" value="true"/>
    <add key="Links.aspx" value="false"/>
    <!-- Dynamic Drop down list keys-->
  </appSettings>
</configuration>
and wrote a method

public void ddlDynamicVisible(string PageName, DropDownList ddlDynamic)
       {
          if (ddlDynamic != null)
          {
                String isVisible = string.Empty;
                Configuration configuration = WebConfigurationManager.OpenWebConfiguration("~");

                AppSettingsSection appSettingsSection = (AppSettingsSection)configuration.GetSection("appSettings");
                if (appSettingsSection != null)
                {
                    foreach (string key in appSettingsSection.Settings.AllKeys)
                    {
                        if (key == PageName)
                        {
                            isVisible = System.Configuration.ConfigurationManager.AppSettings[key];
                            ddlDynamic.Visible = Convert.ToBoolean(isVisible);
                        }
                    }
                }
            }
        }
make a call to this method from each page where you want to display or hide control

public partial class Links : System.Web.UI.Page
    {
        DropDownList ddlDynamic;
        protected void Page_Load(object sender, EventArgs e)
        {
            ddlDynamic = (DropDownList)Master.FindControl("ddlDynamic");
            CustomMethods Methods = new CustomMethods();
            Methods.ddlDynamicVisible(Path.GetFileName(Request.PhysicalPath), ddlDynamic);
        }
    }
now this dropdown will only be available on pages where you set True in web.config.

Thanks,
Enjoy coding.