private async void list_Orders_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems.Count == 0)
{
return;
}
CurrentForm = e.AddedItems[0] as OrderForm;
(PageNav as AllOrdersPageNav).OrderForm = CurrentForm;
await CurrentForm.RetrieveAllOrderItems();
list_OrderItems.ItemsSource = CurrentForm.OrderItems;
(PageNav as AllOrdersPageNav).NotifyOrderFormChanged();
}