how to iterate over controls in page to set properties

[ZeBula8]

using: asp.net 2.0 - [vs2005]

I have a page with a master template named "MasterPage.master" and want to iterate over all of the controls in the Page to set a property.

I tried using this in the Page Unload event:

Dim ctlControl As System.Web.UI.WebControls.WebControl
        For Each ctlControl In Page.Controls
            ctlControl.Enabled = False
        Next

but this gives an exception:

Unable to cast object of type 'ASP.masterpage_master' to type 'System.Web.UI.WebControls.WebControl'.

I tried removing the Master template
but I still get same error but instead of 'ASP.masterpage_master' it
refers to Literal Control.

Am I missing something here?

Please help. Thanks in advance.