Synchronizing Access to a member of the ASP.NET session

Question

I\'m building a Javascript application and eash user has an individual UserSession. The application makes a bunch of Ajax calls. Each Ajax call needs access to a single User

Answer 1

You don't need to lock Session state access.

The physical values of a session state are locked for the time needed to complete a request. The lock is managed internally by the HTTP module and used to synchronize access to the session state.

http://msdn.microsoft.com/en-us/library/aa479041.aspx

Answer 2

In general, you don't need this kind of code for asp.net session access, since access to each session is limited to a single user. The only reason I can think of for locking access to your session object is if you expect to have multiple simultaneous ajax requests, and even so, I think asp.net would synchronize the access for you.

If you do decide to lock, you only really need to do it if your session object is null:

if (context.Session["MySession"] == null) {
  lock(SessionLock) {
    if (context.Session["MySession"] == null) {
      context.Session["MySession"] = new WebSession(context);  // try-catch block removed for clarity (and my laziness)
    }
  }
}
return (WebSession)context.Session["MySession"];