private void syncItemsInListBox(MultiLineListBox listbox, List <string> items)
        {
            try
            {
                List <string> list = new List <string>(items);
                foreach (string item in listbox.Items)
                {
                    if (!list.Contains(item))
                    {
                        listbox.Items.Remove(item);
                    }
                }

                foreach (string item in list)
                {
                    if (!listbox.Items.Contains(item))
                    {
                        listbox.Items.Add(item);
                    }
                }
            }
            catch (InvalidOperationException) { }
        }
 private void Button_Copy_Click(object sender, RoutedEventArgs e)
 {
     Mlb.ShowDialog();
     Mlb = new MultiLineListBox();
 }