private void BtnDelete_Click(object sender, RoutedEventArgs e)
 {
     vm.Delete();
 }
 /// <summary>
 /// Calls the CustomerViewModel Delete method to Delete the selectedCustomer
 /// from the CustomerView
 /// </summary>
 /// <param name="parameter"></param>
 public void Execute(object parameter)
 {
     // get the Id Use that to find the customer in the database
     CustomerView.Delete();
     CustomerView.OnShowDialog();
 }