private void Window_Loaded(object sender, RoutedEventArgs e)
{
gstBDD = new GstBdd();
lstTraders.ItemsSource = gstBDD.getAllTraders();
}
private void lstTraders_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
lstTraders.ItemsSource = null;
lstTraders.ItemsSource = GstBdd.getAllTraders();
}