private void button2_Click(object sender, EventArgs e) { try { clsElement eTemp = new clsElement(); string index = ""; if (lstSelectedEle.SelectedValue == null || String.IsNullOrEmpty(lstSelectedEle.SelectedValue.ToString())) { MessageBox.Show("Sélectionnez un élément de la liste"); } else { index = lstSelectedEle.SelectedValue.ToString(); eTemp = clsGlobals.ListTemp.ElementByID(index); AllElements.AddNotExist(eTemp); clsGlobals.ListTemp.RemoveItem(eTemp); LinkLists(); } } catch (Exception ex) { MessageBox.Show(ex.Message); } }