C# TreeView的CheckBox 父/子节点点击联动选择效果

注：
　　点击时请正常速度点击，不然会出现“奇怪”现象！！！

        /// <summary>
        /// 节点点击 子级->同级->父级
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tvRoles_AfterCheck(object sender, TreeViewEventArgs e)
        {
            if (e.Action != TreeViewAction.ByMouse) return;
            ChildrenChecked(e.Node, e.Node.Checked);
            ParentChecked(e.Node);
        }

        /// <summary>
        /// 把每一个父级当作子级
        /// </summary>
        /// <param name="node"></param>
        /// <returns></returns>
        private void ParentChecked(TreeNode node)
        {
            if (node.Parent == null) return;
            ///单根
            //if (node.PrevNode == null && node.NextNode == null)
            //{
            //    node.Parent.Checked = node.Checked;
            //    return;
            //}
            ///多根
            //当前节点两种状态
            if (!node.Checked)//节点没被选中,父节点不被选中
            {
                node.Parent.Checked = node.Checked;
            }
            else//节点被选中，同级节点决定父节点状态
            {
                node.Parent.Checked = PeerChecked(node);
            }
            ParentChecked(node.Parent);//继续上级忽略同级
        }
        private bool PeerChecked(TreeNode node)
        {
            if (node == null) return true;
            return PeerPrevNodeChecked(node.PrevNode) && PeerNextNodeChecked(node.NextNode);
        }
        private bool PeerNextNodeChecked(TreeNode node)
        {
            if (node == null) return true;
            return PeerNextNodeChecked(node.NextNode) & node.Checked;
        }
        private bool PeerPrevNodeChecked(TreeNode node)
        {
            if (node == null) return true;
            if (node.Checked)
                return PeerPrevNodeChecked(node.PrevNode);
            return false;
        }
        /// <summary>
        /// 把每一个子级当作父级
        /// </summary>
        /// <param name="node"></param>
        /// <param name="check"></param>
        private void ChildrenChecked(TreeNode node, bool check)
        {
            foreach (TreeNode item in node.Nodes)
            {
                ChildrenChecked(item, check);
                item.Checked = check;
            }
        }