The System.Web.Security.AnonymousIdentificationEventHandler delegate is defined for the AnonymousIdentificationModule.Creating event of the System.Web.Security.AnonymousIdentificationModule class. You can access the AnonymousIdentificationModule.Creating event of the System.Web.Security.AnonymousIdentificationModule class by specifying a subroutine named AnonymousIdentification_Creating in the Global.asax file for your ASP.NET application. The AnonymousIdentificationModule.Creating event is raised during the System.Web.HttpApplication.PostAuthenticateRequest event.

The System.Web.Security.AnonymousIdentificationModule constructs an System.Web.Security.AnonymousIdentificationEventArgs object using the current System.Web.HttpContext and passes it to the AnonymousIdentification_Creating event.

You can use the AnonymousIdentificationEventArgs.AnonymousId property of the System.Web.Security.AnonymousIdentificationEventArgs object supplied to the AnonymousIdentification_Creating event to set the anonymous identifier to a custom value. If you do not specify a value for the AnonymousIdentificationEventArgs.AnonymousId property during the AnonymousIdentification_Creating event, a Guid is used.

The AnonymousIdentification_Creating event is only raised when anonymous identification is AnonymousIdentificationModule.Enabled by setting the anonymousIdentification configuration element to true.