C# winform treeView checkbox全选反选

private void treeView2_AfterCheck(object sender, TreeViewEventArgs e)
        {
            if (e.Action != TreeViewAction.Unknown)
            {
                CheckAllChildNodes(e.Node, e.Node.Checked);
                //选中父节点
                bool bol = true;
                if (e.Node.Parent != null)
                {
                    for (int i = 0; i < e.Node.Parent.Nodes.Count; i++)
                    {
                        if (!e.Node.Parent.Nodes[i].Checked)
                            bol = false;
                    }
                    e.Node.Parent.Checked = bol;
                }
            }
        }
        #region  选中子节点
        public void CheckAllChildNodes(TreeNode treeNode, bool nodeChecked)
        {
            foreach (TreeNode node in treeNode.Nodes)
            {
                node.Checked = nodeChecked;
                if (node.Nodes.Count > 0)
                {
                    this.CheckAllChildNodes(node, nodeChecked);
                }
            }
        }
        #endregion