以下是两个示例，用于测试所选单元格的性能和填充样式。由于您的代码段没有显示在什么上下文中调用代码，特别是创建图像列部分，为了避免重复不必要的例程，请使用网格设计器添加4个DataGridViewImageColumn类型的列，并从那里设置自动调整大小和布局属性。

正常模式

在窗体的ctor中，使用Reflection启用网格的DoubleBuffered属性以减少 Flink 。emptyImage位图是空单元格的空值。

public partial class SomeForm : Form
{
    private Bitmap emptyImage;

    public SomeForm()
    {
        dgv.GetType()
            .GetProperty("DoubleBuffered", BindingFlags.Instance | BindingFlags.NonPublic)
            .SetValue(dgv, true);

        emptyImage = new Bitmap(1, 1);

        foreach (var col in dgv.Columns.OfType<DataGridViewImageColumn>())
            col.DefaultCellStyle.NullValue = emptyImage;
    }

覆写OnLoad方法以填入方格或呼叫方格的方法。

protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        var imgFolder = @"Your-Image-Folder-Path";
        LoadImages(imgFolder);
    }

    protected override void OnFormClosed(FormClosedEventArgs e)
    {
        base.OnFormClosed(e);
        emptyImage.Dispose();
    }

    private void LoadImages(string path)
    {            
        string[] allFiles = Directory.GetFiles(path);

        for (int i = 0; i < allFiles.Length; i += 4)
        {
            var files = allFiles.Skip(i).Take(4);

            dgv.Rows.Add(
                files.Select(f =>
                {
                    using (var img = Image.FromFile(f, true))
                        return Thumb.GetThumbnail(img, ThumbSize.LowRes);
                }).ToArray());
        }
    }

注意，您的Thumb.GetThumbnail方法返回一个新图像，因此您需要处理原始图像。
实现CellPainting事件以绘制除DataGridViewPaintParts.SelectionBackground之外的所有内容，并使用半透明颜色填充选定的单元格。

private void dgv_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
    {    
        e.Paint(e.ClipBounds, e.PaintParts & ~DataGridViewPaintParts.SelectionBackground);
    
        if (e.RowIndex >= 0 &&
            e.Value != null && e.Value != emptyImage &&
            (e.State & DataGridViewElementStates.Selected) > 0)
        {            
            using (var br = new SolidBrush(Color.FromArgb(100, SystemColors.Highlight)))
                e.Graphics.FillRectangle(br, e.CellBounds);
        }

        e.Handled = true;
    }
}

虚拟模式

这里你需要让数据存储只缓存你需要显示的图像。可见行的每个单元格的图像。为此，创建了Cache类来管理相关功能，包括：

• 计算每个可见行显示4个图像所需的总行数。因此，在第一次创建网格并调整网格大小时，应调用SetMaxRows方法来重新计算可见行。
• 在Dictionary<int, Image>中加载、创建和缓存当前可见行图像，其中键是单元格编号。
• 引发CellValueNeeded事件时传递请求的图像。

public partial class SomeForm : Form
{
    private readonly Cache cache;

    public SomeForm()
    {
        dgv.GetType()
            .GetProperty("DoubleBuffered", BindingFlags.Instance | BindingFlags.NonPublic)
            .SetValue(dgv, true);
        dgv.VirtualMode = true;

        var imgFolder = @"Your-Image-Folder-Path";
        cache = new Cache(imgFolder, dgv.ColumnCount);
        dgv.RowCount = cache.GetRowCount();
        SetMaxRows();
    }

    protected override void OnFormClosed(FormClosedEventArgs e)
    {
        base.OnFormClosed(e);
        cache.Dispose();
    }

    private void dgv_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e) =>
        e.Value = cache.GetImage(e.RowIndex, e.ColumnIndex);

    private void dgv_Resize(object sender, EventArgs e) => SetMaxRows();

    // Change dgv.RowTemplate.Height as needed...
    private void SetMaxRows() =>
        cache.MaxRows = (int)Math
        .Ceiling((double)dgv.ClientRectangle.Height / dgv.RowTemplate.Height);

    private class Cache : IDisposable
    {
        private readonly Dictionary<int, Image> dict;
        private readonly Bitmap nullImage;
        private int currentRowIndex = -1;

        private Cache()
        {
            dict = new Dictionary<int, Image>();
            nullImage = new Bitmap(1, 1);
        }

        public Cache(string path, int columnCount) : this()
        {
            ImageFolder = path;                
            ColumnCount = columnCount;
        }

        public string ImageFolder { get; set; }
        public int ColumnCount { get; set; }
        public int MaxRows { get; set; }
        public Bitmap NullImage => nullImage;

        public Image GetImage(int rowIndex, int columnIndex)
        {
            var ri = rowIndex - (rowIndex % MaxRows);

            if (ri != currentRowIndex)
            {
                foreach (var img in dict.Values) img?.Dispose();
                currentRowIndex = ri;
                dict.Clear();
            }

            var i = (rowIndex * ColumnCount) + columnIndex;
            Image res = nullImage;

            if (!dict.ContainsKey(i))
            {
                var file = Directory.EnumerateFiles(ImageFolder)
                    .Skip(i).FirstOrDefault();

                if (file != null)
                {
                    using (var img = Image.FromFile(file, true))
                        dict[i] = res = Thumb.GetThumbnail(img, ThumbSize.LowRes);
                }
            }
            else
            {
                res = dict[i];
            }

            return res;
        }

        public int GetRowCount()
        {
            var count = Directory.EnumerateFiles(ImageFolder).Count();
            return (int)Math.Ceiling((double)count / ColumnCount);
        }

        public void Dispose()
        {
            foreach (var img in dict.Values) img?.Dispose();
            nullImage.Dispose();
        }
    }

最后，CellPainting事件几乎保持不变，只是您从cache示例获取了空图像。

private void dgv_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
    {
        e.Paint(e.ClipBounds, e.PaintParts & ~DataGridViewPaintParts.SelectionBackground);

        if (e.RowIndex >= 0 &&
            e.Value != null && e.Value != cache.NullImage &&
            (e.State & DataGridViewElementStates.Selected) > 0)
        {                
            using (var br = new SolidBrush(Color.FromArgb(100, SystemColors.Highlight)))
                e.Graphics.FillRectangle(br, e.CellBounds);
        }

        e.Handled = true;
    }
}