private void buttonAdd_Click(object sender, EventArgs e) { try { nc.addNumber(textBoxNumber.Text); listBoxNumber.DataSource = nc.getNumbers(); textBoxNumber.Text = string.Empty; textBoxNumber.Focus(); } catch (ControllerException ce) { errorProviderAdd.SetError(buttonAdd, ce.Message); } catch (Exception ex) { Debug.WriteLine(ex.Message); } if (listBoxNumber.Items.Count > 0) { felfedPaneleket(); } else { eltakarPaneleket(); } }