webforms - Asp.Net not using the handler resolved in PageHandlerFactory -

i trying intercept calling of pages in asp.net, can change object before used.
providing simplified code, illustrate problem.
debugging, step custompagehandlerfactory, , see using base method instance of page. instance not seem passed forward.
hashcode of gethandler's object , instance's hashcode of page differ.

shouldn't same?

the page:

public partial class _default : page {     public bool throw { get; set; }      public _default()     {         throw = true;     }      protected void page_load(object sender, eventargs e)     {         throwexception();     }      public virtual void throwexception()      {         if (throw)         {             throw new exception("non sense error!");         }                 } } 

the handlerfactory:

public class custompagehandlerfactory : pagehandlerfactory {     public override ihttphandler gethandler(httpcontext context, string requesttype, string virtualpath, string path)     {         var page = base.gethandler(context, requesttype, virtualpath, path);          ((_default)page).throw = false;          return page;     } } 

and chunk of config:

(...) <system.webserver>     <handlers>         <add name="custompagehandler" path="*.aspx" verb="*" type="example.custompagehandlerfactory" />     </handlers>     <validation validateintegratedmodeconfiguration="false" /> </system.webserver>  <system.web>     <httphandlers>               <remove verb="*" path="*.aspx" />         <add verb="*" path="*.aspx" type="example.custompagehandlerfactory" />     </httphandlers>     (...) 

as pointed out @ondrej svejdar, should add framework versions:

• c# 4.5
• asp.net 4.0
• iis 7.5
• visual studio 2013