.net不让浏览器缓存

// 不让浏览器缓存
context.Response.Buffer = true ;
context.Response.ExpiresAbsolute = DateTime.Now.AddDays( - 1 );
context.Response.AddHeader( " pragma " , " no-cache " );
context.Response.AddHeader( " cache-control " , "" );
context.Response.CacheControl = " no-cache " ;
context.Response.ContentType = " text/plain " ;