Asp.net gives you a built-in object called Session that lets you store
whatever you want in it;

Session["UserID"] = 123;
Session["Username"] = "Hello";
User user = new User();
Session["UserObject"] = user;

So you could create your own MySession class and just store it in the
Session object;

MySession s = new MySession();
Session["SessionObject"] = s;

then retrieve it like this;

MySession s = (MySession) Session["SessionObject"];

If you look at the global.asax page you can code up a Session start event,
this is fired when the user first visits your site and this is where you
would instantiate the object and store it in the Session;

void Session_Start(object sender, EventArgs e)
{
   ... code here
}

on 28-3-2008, chowchho supposed :

It might not be so easy to "pass it from page to page", as the
page-classes themselves live only long enough to serve a single
request. Every request is handled by a fresh instance of the page.
This means that you can't just access a property of an instance of some
other page, as that instance does not exist.

An other "solution" that might occur to you is to use a singleton.
DO NOT DO THAT. The web application is a single application that serves
a number of users. If you use a singleton to store information, then
EVERY user sees the same information. This might or might not be what
you want.

That is the reason that the Session is available in web applications:
here you can store user-specific information (or rather *session*
specific information). This session usually depends on a temporary
cookie.

Hans Kesting

I really like this approach:

http://aspalliance.com/810_Implementing_a_Singleton_Pattern_in_C

I'm looking to extending it (one day) and be able to swap out which "store"
is being used based on key.

So I could decide to configuration wise....change whether or not I use
Session or ViewState .(as one permutation example) based on a simple
string/key.

..

But what he has is good as is.

You could start by using the built in session mechanism this way :
http://www.codeproject.com/KB/aspnet/typedsessionstate.aspx

From this starting point point you'll have the flexibility to change the
underlying store and have the benefit of strongly typed access with
intellisense...

--
Patrice