public ShellViewModel(IEventAggregator agg)
{
_eventAgg = agg;
_conductor = new Conductor <IScreen> {
Parent = this
};
_conductor.ConductWith(this);
_conductor.AttachToPropertyChanged(() => _conductor.ActiveItem, () => NotifyOfPropertyChange(() => MainActiveItem));
_conductor.ActivateItem(new MainViewModel());
}
