CustomerOrderDetailsViewModel.cs

namespace MongoDBApp.ViewModels
{
    [ImplementPropertyChanged]
    public class CustomerOrdersViewModel : IPageViewModel
    {

        public ICommand EditCommand { get; set; }
        private IDialogService _dialogService; 

        public CustomerOrdersViewModel(IDialogService dialogservice)
        {
            this._dialogService = dialogservice;
            Messenger.Default.Register<UpdateProductMessage>(this, OnUpdateProductMessageReceived);
            LoadCommands();
            
        }


        public ProductModel SelectedProduct { get; set; }

        #region methods
        
        private void LoadCommands()
        {
            EditCommand = new CustomCommand(EditOrder, CanModifyOrder);
        }

        private bool CanModifyOrder(object obj)
        {

            if (SelectedOrder != null && SelectedOrder.Email != null && SelectedOrder.Date != null &&
                SelectedOrder.Id != null && SelectedProduct != null )
            {
                return true;
            }

            return false;
        }

        private void EditOrder(object obj)
        {
            Messenger.Default.Send<ProductModel>(SelectedProduct);
            _dialogService.ShowDetailDialog();
        }

        #endregion

    }
}

ProductViewModel.cs

namespace MongoDBApp.ViewModels
{
    [ImplementPropertyChanged]
    class ProductViewModel 
    {

        public ProductViewModel()
        {

            Messenger.Default.Register<ProductModel>(this, OnProductReceived);

        }

        public ProductModel SelectedProduct { get; set; }
  

        #region methods

        public void OnProductReceived(ProductModel product)
        {
            SelectedProduct = product;
        }

  
        #endregion
    }
}