why I can't use code files from app_code in my code asp.net c# -

i working on asp.net web app, , have few classes in app_code, reason can't use of them in code. tried using same namespace, tried without namespace in both files, nothing helps.

this page code:

using system; using system.collections.generic; using system.linq; using system.web; using system.web.ui; using system.web.ui.webcontrols; using linkedin; using linkedin.serviceentities;   namespace authentication {     public partial class linkedinmoreinfo : linkedinbasepage     {         protected void page_load(object sender, eventargs e)         {          }     } } 

and code in class:

using system; using system.data; using system.configuration; using system.linq; using system.web; using system.web.security; using system.web.ui; using system.web.ui.htmlcontrols; using system.web.ui.webcontrols; using system.xml.linq;  using linkedin;  namespace authorisation {     public class linkedinbasepage : system.web.ui.page     {         private string accesstoken         {             { return (string)session["accesstoken"]; }             set { session["accesstoken"] = value; }         }          private inmemorytokenmanager tokenmanager         {                         {                 var tokenmanager = (inmemorytokenmanager)application["tokenmanager"];                 if (tokenmanager == null)                 {                     string consumerkey = configurationmanager.appsettings["linkedinconsumerkey"];                     string consumersecret = configurationmanager.appsettings["linkedinconsumersecret"];                     if (string.isnullorempty(consumerkey) == false)                     {                         tokenmanager = new inmemorytokenmanager(consumerkey, consumersecret);                         application["tokenmanager"] = tokenmanager;                     }                 }                  return tokenmanager;             }         }          protected weboauthauthorization authorization         {             get;             private set;         }          protected override void onload(eventargs e)         {             this.authorization = new weboauthauthorization(this.tokenmanager, this.accesstoken);              if (!ispostback)             {                 string accesstoken = this.authorization.completeauthorize();                 if (accesstoken != null)                 {                     this.accesstoken = accesstoken;                      response.redirect(request.path);                 }                  if (accesstoken == null)                 {                     this.authorization.beginauthorize();                 }             }              base.onload(e);         }     } } 

any idea can problem? in advance

go properties of files, , change build action compile