private void ContainerTypes_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            //load container names combo box
            KeyValuePair <long, string> s = (KeyValuePair <long, string>)((ComboBox)sender).SelectedValue;

            MainWindow wnd = Application.Current.MainWindow as MainWindow;
            List <ContainerNameDTO> containerNames = wnd.GetContainerNamesByType(s.Key);

            ObservableCollection <KeyValuePair <long, string> > list2 = new ObservableCollection <KeyValuePair <long, string> >();

            foreach (ContainerNameDTO dto in containerNames)
            {
                list2.Add(new KeyValuePair <long, string>(dto.ContainerNameId, dto.ContainerName));
            }

            this.ContainerNames.ItemsSource = null;
            this.ContainerNames.ItemsSource = list2;
        }