Modify the ASP.NET Session during debug?

Question

Is it possible to modify values, keys or even clear the Session during debugging of an ASP.NET page?
I tried the following in the Immediate Window (in the presented order), but nothing changed the Session object:

Session.Clear()
Expression has been evaluated and has no value

Session.Keys
{System.Collections.Specialized.NameObjectCollectionBase.KeysCollection}
    Count: 12

Session.Clear()
Expression has been evaluated and has no value

Session.Keys[0]
"user_id"

Session.Abandon()
Expression has been evaluated and has no value

Session["user_id"]
3

Edit: OK, it looks like I can sometimes change it. This is very puzzling. If someone knows why it's sometimes failing, I'd appreciate having that knowledge.

Answer 1

You can change the Session with the Intermediate and Command Windows in debug mode.
Just make sure you don't have any code (e.g., the getter of a property, a rogue Trace Point that prints a "message" like {HttpContext.Current.Session["some_key"] = [some value];}, etc.), that resets the values after you make the changes.

(Lesson learned.)