If you have Master page for your website then you must be needing reference to its controls from the child content page. There are various ways to do it. To get strong access between master and content page you can add @ MasterType directive to your content page. For example if your Page directive has masterPageFile = " ~/MyMasterPage.master" , then you have to add following line to aspx page.
<%@ MasterType virtualPath=~/MyMasterPage.master" %>
Now you can access public properties of master page from content page. To locate specific control we can use FindControl method:
Label myHeaderLabel = (Label) Master.FindControl("lblmasterHeader"); // lblmasterHeader is the ID of label