Global.asax, Application and Session Objects

When a Web Service runs, it has access to the Application and Session objects. These are objects provided by ASP.NET through which you can manage the execution of the Web Service. ASP.NET creates an Application object when it first starts the Application, that is, when any client requests any Web Service or Web Page stored in the same IIS Virtual Directory. It also creates a Session object for each client process.

When the first request comes in for an ASP.NET application, ASP.NET checks for an optional file named global.asax, and if it is there it compiles it. The application's global.asax instance is then used to apply application events.

global.asax typically defines callback functions to be executed on the various Application and Session events, such as Application_Start, Application_End, Session_Start, Session_End and so forth.

Dyalog allows you to use APL functions in the global.asax script. This allows you to initialise your APL application when it is first invoked, and to close it down cleanly when it is terminated.

For example, you can use global.asax to tie a component file on start-up, and untie it on termination.