When's the earliest i can access some Session

问题:

i want to check if the Session contains some key/value data, in my global.asax. I'm not sure when the earliest possible time (and method name) is, to check this.

thanks :)

回答1:

I always believed Application_AcquireRequestState was the first event in Global.asax that could access the current session. It's definitely not Application_BeginRequest.

回答2:

MSDN casually mentions that the session state is acquired during Application_PostAcquireRequestState event. I wish it was restated at the Life Cycle Overview page.

The latest you can access session state is in Application_PostRequestHandlerExecute, as it is saved by SessionStateModule during the next event Application_ReleaseRequestState.

回答3:

You need to use BeginRequest (http://msdn.microsoft.com/en-us/library/system.web.httpapplication.beginrequest.aspx) as it is the first event fired on the HttpApplication object (which the Global.asax inherits).

You'll see more about the ASP.NET Application Lifecycle here - http://msdn.microsoft.com/en-us/library/ms178473.aspx (this is for IIS 5 & IIS 6).

回答4:

According to link text, the earliest events in global.asax that you can access session objects is when global.asax fires Session_Start event

Session__Start: Fired when a new user visits the application Web site.
Session__End: Fired when a user's session times out, ends, or they leave the application Web site