c#，winform，treeview，选中节点，选中相应的全部子节点，取消节点，取消父节点

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication6
{
    public partial class TreeViewTest : Form
    {
        public TreeViewTest()
        {
            InitializeComponent();
        }

        private void TreeViewTest_Load(object sender, EventArgs e)
        {
            treeView1.ExpandAll();
        }

        private void treeView1_AfterCheck(object sender, TreeViewEventArgs e)
        {

            if (e.Action == TreeViewAction.ByMouse)
            {
                textBox1.Text = e.Node.Text;
                if (e.Node.Checked)
                {
                    //取消节点选中状态之后，取消所有父节点的选中状态
                    setChildNodeCheckedState(e.Node, true);
                   
                }
                else
                {
                    //取消节点选中状态之后，取消所有父节点的选中状态
                    setChildNodeCheckedState(e.Node, false);
                    //如果节点存在父节点，取消父节点的选中状态
                    if (e.Node.Parent != null)
                    {
                        setParentNodeCheckedState(e.Node, false);
                    } 
                }
            }
        }
        //取消节点选中状态之后，取消所有父节点的选中状态
        private void setParentNodeCheckedState(TreeNode currNode, bool state)
        {
            TreeNode parentNode = currNode.Parent;
            
                parentNode.Checked = state;
                if (currNode.Parent.Parent != null)
                {
                    setParentNodeCheckedState(currNode.Parent, state);
                }
        }
        //选中节点之后，选中节点的所有子节点
        private void setChildNodeCheckedState(TreeNode currNode, bool state)
        {
            TreeNodeCollection nodes=currNode.Nodes;
            if(nodes.Count>0)
            foreach (TreeNode tn in nodes)
            {
                
                tn.Checked = state;
                setChildNodeCheckedState(tn, state);
            }
        }
    }
}