C# MVVM - shared object - NotifyOfPropertyChange

Question

I'm doing a intro c# MVVM project (Caliburn.Micro) and I'm injecting a "job" object into each viewmodel so that the job information is accessible everywhere.

I was hoping that changes to the injected object, which might be affected by a method in one viewmodel, would be reflected in all viewmodels, and this appears to be the case, however how would the bound properties associated with that injected object be updated?

For eg. below: The instance of JobClass is passed around and is changed by the MenuBarViewModel. How would one trigger the NotifyOnPropertyChange() in the property in the MainPanelViewModel so a bound xaml control in the associated view would pick up on the changes to the underlying member.

Or is this not how is should work. Is this what the event aggregator is supposed to manage? I was hoping that passing around the job would simplify things, or is that the global variable issue... Any tips would be welcome!

Hanuman....

// MainWindowViewModel

public class MainWindowViewModel
    {

        private JobClass _jobClass;
        private readonly IEventAggregator _eventAggregator;

        public MenuBarViewModel MenuBarViewModel { get; set; }
        public MainPanelViewModel MainPanelViewModel { get; set; }

        public MainWindowViewModel()
        {
            _eventAggregator = new EventAggregator();
            _jobClass= new JobClass ();

            this.MenuBarViewModel = new MenuBarViewModel(_eventAggregator, _jobClass);
            this.MainPanelViewModel = new MainPanelViewModel(_eventAggregator, _jobClass);

        }
   }

// MenuBarViewModel

 public class MenuBarViewModel: PropertyChangedBase
    {
        IEventAggregator _events;
        JobClass _jobClass;

        public MenuBarViewModel(IEventAggregator eventAggregator, JobClass jobClass)
        {
            _events = eventAggregator;
            _jobClass = JobClass;
        }

        public SomeMethod()
        {
          _jobClass.MethodToAddSomedata();
         }

// MainPanelViewModel

public class MainPanelViewModel : PropertyChangedBase
    {
        IEventAggregator _events;
        JobClass _jobClass;

         public JobClass JobCase
        {
            get { return _jobClass; }
            set
            {
                _jobClass= value;
                NotifyOfPropertyChange(() => JobCase);
            }
        }

}