private void AddOrder_Click(object sender, RoutedEventArgs e)
 {
     if (BL.SingletonFactoryBL.GetBL().GetHostingUnitsOfHost(host).Count == 0)
     {
         MessageBox.Show("You don't have any hosting unit.", "Error!", MessageBoxButton.OK, MessageBoxImage.Error);
     }
     else
     {
         Window addOrderWindow = new AddOrderWindow(host);
         addOrderWindow.Show();
         this.Close();
     }
 }
        private void AddOrder_Click(object sender, RoutedEventArgs e)
        {
            Window addOrder = new AddOrderWindow();

            addOrder.Show();
        }