TreeView拖动节点上下移动

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

namespace TreeViewDropNodeDemo
{
    public partial class Form1 : Form
    {
        public Form1（）
        {
            InitializeComponent（）;

            CreateTreeView（）;//构建树
        }

        private void CreateTreeView（）
        {
            treeView1.Nodes.Add（“北京“）;
                treeView1.Nodes[0].Nodes.Add（“昌平区“）;
                treeView1.Nodes[0].Nodes.Add（“通州区“）;
                treeView1.Nodes[0].Nodes.Add（“海淀区“）;
            treeView1.Nodes.Add（“河北省“）;
                treeView1.Nodes[1].Nodes.Add（“石家庄市“）;
                treeView1.Nodes[1].Nodes.Add（“唐山市“）;
                treeV

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2019-05-28 15:51  TreeViewDropNodeDemo\
     目录           0  2019-05-28 16:05  TreeViewDropNodeDemo\TreeViewDropNodeDemo\
     文件        2261  2019-05-28 15:58  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Form1.Designer.cs
     文件        4278  2019-05-28 16:05  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Form1.cs
     文件        5817  2019-05-28 15:58  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Form1.resx
     文件         481  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Program.cs
     目录           0  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Properties\
     文件        1382  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Properties\AssemblyInfo.cs
     文件        2892  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Properties\Resources.Designer.cs
     文件        5612  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Properties\Resources.resx
     文件        1107  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Properties\Settings.Designer.cs
     文件         249  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\Properties\Settings.settings
     文件        3563  2019-05-28 15:55  TreeViewDropNodeDemo\TreeViewDropNodeDemo\TreeViewDropNodeDemo.csproj
     目录           0  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\bin\
     目录           0  2019-05-28 15:55  TreeViewDropNodeDemo\TreeViewDropNodeDemo\bin\Debug\
     文件        9728  2019-05-28 16:01  TreeViewDropNodeDemo\TreeViewDropNodeDemo\bin\Debug\TreeViewDropNodeDemo.exe
     文件       26112  2019-05-28 16:01  TreeViewDropNodeDemo\TreeViewDropNodeDemo\bin\Debug\TreeViewDropNodeDemo.pdb
     文件       21656  2019-05-28 16:02  TreeViewDropNodeDemo\TreeViewDropNodeDemo\bin\Debug\TreeViewDropNodeDemo.vshost.exe
     文件         490  2013-03-18 17:00  TreeViewDropNodeDemo\TreeViewDropNodeDemo\bin\Debug\TreeViewDropNodeDemo.vshost.exe.manifest
     目录           0  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\
     目录           0  2019-05-28 16:01  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\
     文件         791  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\DesignTimeResolveAssemblyReferences.cache
     文件        6124  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\DesignTimeResolveAssemblyReferencesInput.cache
     目录           0  2019-05-28 16:12  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\TempPE\
     文件         180  2019-05-28 15:58  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\TreeViewDropNodeDemo.Form1.resources
     文件         180  2019-05-28 15:55  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\TreeViewDropNodeDemo.Properties.Resources.resources
     文件         807  2019-05-28 16:02  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\TreeViewDropNodeDemo.csproj.FileListAbsolute.txt
     文件         847  2019-05-28 15:58  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\TreeViewDropNodeDemo.csproj.GenerateResource.Cache
     文件        9728  2019-05-28 16:01  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\TreeViewDropNodeDemo.exe
     文件       26112  2019-05-28 16:01  TreeViewDropNodeDemo\TreeViewDropNodeDemo\obj\Debug\TreeViewDropNodeDemo.pdb
     文件        1029  2019-05-28 15:51  TreeViewDropNodeDemo\TreeViewDropNodeDemo.sln
............此处省略1个文件信息