How to make the page expire?

.1 the html code
<meta   http-equiv="pragma"   content="no-cache">  
  <meta   http-equiv="cache-control"   content="no-cache,   must-revalidate">  
  <meta   http-equiv="expires"   content="0">  
2. make the page expire at once.
Response.Cache.SetCacheability(HttpCacheability.NoCache);  
or.
Response.Expires   =   0;  
  Response.ExpiresAbsolute   =   DateTime.Now;  
  Response.AddHeader("pragma",   "no-cache");  
  Response.CacheControl   =   "no-cache";