title: When I read the querystring? In the Event PageLoad? Best Practice
body: <p>I need to work with querystring but i'm not sure when i shoud use. Permissions in my page depend of querystring. </p>
  
  <p>I know, i can use in page_load but i need to be sure this is a best practice.</p>
  
  <p>[EDIT]</p>
  
  <p>If I use querystring to <strong>permissons in my pag</strong>e when i shoud use querystring?</p>
  
  <p>Example:
  Show some controls hide others.</p>
  
  <p>[/EDIT]</p>
  
  <p>Sorry my bad english!</p>
  
  <p>Thanks! </p>