Is there a way to use "if" condition inside DDX?

I need to enable page numbering in result PDF file as per the value of a variable dynamically. Is there a way to use "if" condition inside DDX so that I can check the value of the variable (lets say 'true' or 'false') and include the page number tag

          <p>

            Page

            <_PageNumber/>

            of

            <_LastPageNumber/>

          </p>