下面我尝试移动item4来代替item5，我预期的操作是项目4位于item5之上，项目5位于item4之下：

下面我尝试移动item4来代替item5，我预期的操作是item4位于item5之上，item5位于item4之下：

我也不能移动一个项目的地方另一个，谁能帮助？
我在这里留下完整的代码，包括设计：

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

namespace WindowsFormsApp3
{
    public partial class Form1 : Form
    {
        private ListView listView;
        private ListViewItem currentVieItem;
        public Form1()
        {
            InitializeComponent();
            
            createListview();
        }

        public void createListview()
        {
            listView = new ListView();
            listView.AllowDrop = true;

            listView.ItemDrag += new ItemDragEventHandler(OnItemDrag);
            listView.DragOver += new DragEventHandler(OnDragOver);
            listView.DragDrop += new DragEventHandler(OnDragDrop);

            // MY CODE HERE
            ColumnHeader columnHeader = new ColumnHeader();
            listView.Columns.AddRange(new System.Windows.Forms.ColumnHeader[] {
            columnHeader});
            listView.HideSelection = false;
            int indexGroup = 1;
            ListViewGroup group = new ListViewGroup();
            for (int i = 0; i < 100; i++)
            {
                if (i % 5 == 0)
                {
                    string nmGroup = $"Group {indexGroup}";
                    group = new ListViewGroup() { Header = nmGroup};
                    listView.Groups.Add(group);
                    indexGroup++;
                }
                listView.Items.Add(new ListViewItem() { Text = $"Item {i}", Group = group });
            }
            listView.Location = new System.Drawing.Point(12, 12);
            listView.Name = "listView1";
            listView.Size = new System.Drawing.Size(436, 494);
            listView.TabIndex = 0;
            listView.UseCompatibleStateImageBehavior = false;
            listView.View = System.Windows.Forms.View.Details;
            // 
            // columnHeader1
            // 
            columnHeader.Text = "Items";
            columnHeader.Width = 382;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(937, 600);
            this.Controls.Add(listView);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
        }

        public void OnDragOver(object sender, DragEventArgs e)
        {
            var pos = listView.PointToClient(new Point(e.X, e.Y));
            var hit = listView.HitTest(pos);
            this.currentVieItem = hit.Item;
            this.Text = hit.Item?.Index.ToString();

            if (e.Data.GetDataPresent(typeof(ListView.SelectedListViewItemCollection)))
            {
                e.Effect = e.AllowedEffect;
            }
        }

        public void OnDragDrop(object sender, DragEventArgs e)
        {
            if (currentVieItem == null) return;

            int index = currentVieItem.Index;
            this.Text = index.ToString();

            if (e.Data.GetDataPresent(typeof(ListView.SelectedListViewItemCollection)))
            {
                if (e.Effect == DragDropEffects.Move)
                {
                    foreach (ListViewItem current in (ListView.SelectedListViewItemCollection)e.Data.GetData(typeof(ListView.SelectedListViewItemCollection)))
                    {
                        current.Remove();
                        current.Group = currentVieItem.Group;
                        listView.Items.Insert(index, current);
                        index++;
                    }
                }                   
            }
        }

        public void OnItemDrag(object sender, ItemDragEventArgs e)
        {
            listView.DoDragDrop(listView.SelectedItems, DragDropEffects.Move);
        }
    }
}