private void AddAppService() { Messenger.Default.Register <NotificationMessageAction <Cloud> >(this, message => { if ( message.Notification.Equals( Messages. SetAddApplicationServiceData)) { message.Execute(SelectedCloud); } }); Messenger.Default.Send(new NotificationMessageAction <bool>(Messages.AddApplicationService, (confirmed) => Messenger.Default .Send( new NotificationMessageAction < AddApplicationServiceViewModel >( Messages . GetAddApplicationServiceData, ( viewModel) => { if ( !ApplicationServices . Contains (viewModel . SelectedService, new ProvisionedServiceEqualityComparer ())) { ApplicationServices . Add (viewModel . SelectedService); } })))); }