How would that help the OP though - Page_Load event fires before OnClick
event (which I would guess is where you would set the session value).

Here's the reason i ask:

i have an UpdatePanel that contains a div which contains my web user control
called CalendarHelper.ascx. The user control consists of a textbox, calendar
image button, and calendar to help with date entry. I can load this user
control dynamically but whenever i click the calendar icon to make the
calendar appear the webcontrol just disappears on postback/async callback.

This is the only code i have and thought i would need:

protected void BtnEdit_Click(object sender, EventArgs e)
   {                
       CalendarHelper cal1 = new CalendarHelper();
       cal1 = (CalendarHelper)cal1.LoadControl("CalendarHelper.ascx");      
 
       divmain.Controls.Add(cal1);
   }

p.s. i know there is an easier way to do this but i have to work with the
user control that i've been given.