public override void OnNavigatedFrom(Dictionary <string, object> viewModelState, bool suspending)
        {
            if (viewModelState == null || viewModelState.Count == 0)
            {
                return;
            }

            ShippingAddressViewModel.OnNavigatedFrom(viewModelState["ShippingViewModel"] as Dictionary <string, object>, suspending);
            BillingAddressViewModel.OnNavigatedFrom(viewModelState["BillingViewModel"] as Dictionary <string, object>, suspending);
            PaymentMethodViewModel.OnNavigatedFrom(viewModelState["PaymentMethodViewModel"] as Dictionary <string, object>, suspending);
            base.OnNavigatedFrom(viewModelState, suspending);
        }
 public override void OnNavigatedFrom(Dictionary <string, object> viewModelState, bool suspending)
 {
     BillingAddressViewModel.OnNavigatedFrom(viewModelState, suspending);
 }