The CreateUserWizard.CreatingUser event is raised prior to calling the System.Web.Security.MembershipProvider.CreateUser(string, string, string, string, string, bool, object, System.Web.Security.MembershipCreateStatus@) method on the membership provider specified in the CreateUserWizard.MembershipProvider property.
Use the CreateUserWizard.CreatingUser event to establish defaults or modify the information entered by the user before passing the information to the membership provider.
For more information about handling events, see Consuming Events.