What can prevent ASP.NET Session ?

Question

I built a small ASP.NET application. It has a global.asax and sets some session variables on Session_Start(...).

What could prevent (all) session variables from not being set? Would a session time out do it? What if JavaScript turned off? What else can do it?

Answer 1

Turning session off in the web.config file or machine.config file would do it (eg. <sessionState mode="Off" />)

Setting EnableSessionState="false" in your Page directives would also do it.

Is this actually happening to you? What do you mean "prevent them from being set". Is Session_Start not firing? Or it's firing, they're being set, and then they're not set later?

Answer 2

In addition to womp:

• Not having cookies enabled
• Redirecting immediately after setting the session variable(s)

I would suspect the second one in particular, especially if you're using any sort of urlrewriting mechanism that does a Response.Redirect.