Retail_manager/RMWPFUserInterface/ViewModels/ShellViewModel.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Caliburn.Micro;
using RMWPFUserInterface.EventModels;

namespace RMWPFUserInterface.ViewModels
{
    public class ShellViewModel : Conductor<Object>, IHandle<LogOnEvent>
    {
        private IEventAggregator _events;
        private SalesViewModel _salesVM;
        private SimpleContainer _container;
        public ShellViewModel(IEventAggregator events, SalesViewModel salesVM,
            SimpleContainer container)
        {
            _salesVM = salesVM;
            _container = container;
            _events = events;

            _events.SubscribeOnUIThread(this);
         
            ActivateItemAsync(_container.GetInstance<LoginViewModel>());
        }

        public Task HandleAsync(LogOnEvent message, CancellationToken cancellationToken)
        {
            ActivateItemAsync(_salesVM);

            return Task.CompletedTask;
        }
    }
}