Why Cannot Get Access to Session Variables in Constructor?

Question

User1791176437 posted

I find that if I try to get access to any session variable in a class constructor, I will get this error message:

   "Session state can only be used when enableSessionState is set to true, either in a configuration file or in the Page directive"

I have worked around this problem by restoring session state in Page_Load() event handler instead of in the class constructor.

Seem to me that the best place to restore session state for a class object is to restore its session variables in the class constructor.  Therefore, I would like to find a way to fix this problem in a way that I can restore session state in the class constructor.  If this can be done, please tell me how.  If this cannot be done, please also let me know and I will stick with doing this in Page_Load().

By the way, I am using Visual Studio 2003 with .NET 1.1.

Thanks in advance for any info.

Jay Chan

Answer 1

User-158764254 posted

you wont be able to use the constructor.  

The page goes through a life-cycle and Session state is not made available until part way through that lifecycle when the AcquireRequestState event fires: http://msdn.microsoft.com/en-us/library/0dbhtdck.aspx.

you can see the life-cycle here: http://forums.asp.net/t/1191194.aspx

So you'll want to stick with a page lifecycle event such as init or load.

Answer 2

User1791176437 posted

Thanks for letting me know that I cannot restore/save session variables in constructor or destructor and must do those things in Page_Load.

OK, this means I can only do save/restore session variables in classes that have Page_Load, and cannot do this for generic classes that don't have Page_Load event.  The classes that have Page_Load event will have to take care of maintaining session state of classes that don't have Page_Load event.  This is fine with me.

Jay Chan