How can we use global.asax in asp.net? And what is that?
The root directory of a web application has a special significance and certain content can be present on in that folder. It can have a special file called as “Global.asax”. ASP.Net framework uses the content in the global.asax and creates a class at runtime which is inherited from HttpApplication. During the lifetime of an application, ASP.NET maintains a pool of Global.asax derived HttpApplication instances. When an application receives an http request, the ASP.Net page framework assigns one of these instances to process that request. That instance is responsible for managing the entire lifetime of the request it is assigned to and the instance can only be reused after the request has been completed when it is returned to the pool. The instance members in Global.asax cannot be used for sharing data across requests but static member can be. Global.asax can contain the event handlers of HttpApplication object and some other important methods which would execute at various points in a web application