private void onTabPageSelected(object sender, TabControlEventArgs e)
 {
     listBoxItem.Items.Clear();
     foreach (DataType dt in _listTypes)
     {
         if (_classes[tabControlLibrary.SelectedIndex] != dt.GetType()) continue;
         listBoxItem.Items.Add(new ListBoxItem(dt));
     }
     if (listBoxItem.Items.Count > 0)
     {
         listBoxItem.SelectedIndex = 0;
         listBoxItem.Show(); graphCtrl.Show(); tbItem.Show();
     }
     else
     {
         _dt = null;
         listBoxItem.Hide(); graphCtrl.Hide(); tbItem.Hide();
     }
 }
 public ListBoxItem(DataType dt)
 {
     _dt = dt;
 }
 private void listBoxItem_SelectedIndexChanged(object sender, EventArgs e)
 {
     ListBoxItem lbItem = listBoxItem.SelectedItem as ListBoxItem;
     if (null != lbItem)
         _dt = lbItem.DataType;
     else
         _dt = null;
     // update image control
     if (null == _dt || _dt is DataPalletFilm)
         graphCtrl.Hide();
     else
         graphCtrl.Invalidate();
     // update text box
     tbItem.Text = _dt.ToString();
 }