TreeView的子節點和父節點級聯選中

 ///

    /// 選中父節點，其所有子節點也選中
    /// </summary>
    /// <param name="parentNode"></param>
    private void SetChildChecked(TreeNode parentNode)
    {
        foreach (TreeNode tn in parentNode.ChildNodes)
        {
            tn.Checked = true;

            if (tn.ChildNodes.Count > 0)
            {
                SetChildChecked(tn);