Asp. Global.asax in net and the life cycle of Web applications

Asp. Global.asax in net and the life cycle of Web applications
Global.asax files, sometimes called asp.net application files, provide a way to respond to application-level or module-level events in a central location. You can use this file to implement security for your application and some other tasks.
The Global.asax file is configured for any direct HTTP request (via URL) to be rejected automatically, so the user cannot download or view its contents. The ASP.net page framework automatically identifies any changes made to the Global.asax file. After the Global.asax is changed, the asp.net page framework restarts the application, including closing all browser sessions, removing all state information, and restarting the application domain.
The Global.asax file inherits from the HttpApplication class, which maintains a pool of HttpApplication objects and assigns objects from the object pool to the application when needed. The Global.asax file contains the following events:
· Application_init: This event is triggered when an application is instantiated or when it is invoked for the first time. It will be invoked for all HttpApplication object instances.
· Application_disposed: Triggers before the application is destroyed. This is the ideal place to clear previously used resources.
· Application_Error: The event is triggered when an unhandled exception is encountered in the application.
· Application_Start: The event is triggered when the first instance of the HttpApplication class is created. It allows you to create objects that can be accessed by all HttpApplication instances.
· Application_End: The event is triggered when the last instance of the HttpApplication class is destroyed. It is only triggered once in the life cycle of an application.
· Application_BeginRequest: Triggered when an application request is received. For a request, it is the first event that is triggered, and the request is typically a page request (URL) entered by the user.