private void simpleButton1_Click(object sender, EventArgs e)
        {
            CalcCheckedNodesOperation operation = new CalcCheckedNodesOperation();

            treeList1.NodesIterator.DoOperation(operation);
            UpdateList(operation);
        }
 private void UpdateList(CalcCheckedNodesOperation operation)
 {
     listBoxControl1.Items.Clear();
     listBoxControl1.Items.AddRange(operation.CheckedNodes.ToArray());
 }