如何使用DirectoryInfo和FileInfo获取所有文件并将排序后的文件添加到列表中

我想根据它们对文件进行排序List以稍后在方法中使用它们：

dirinfo = new DirectoryInfo(radarImagesDirectory);
var ordered = dirinfo.EnumerateFiles("*.gif")
         .OrderByDescending(f => f.LastWriteTime);
FileInfo newest = ordered.FirstOrDefault();
FileInfo oldest = ordered.LastOrDefault();

我想使用这种方法中的排序文件：

private List<Bitmap> ConvertTo24(List<string> ListinputFileName)
        {
            Bitmap bmpIn = null;
            for (int i = 0; i < ListinputFileName.Count; i++)
            {
                bmpIn = (Bitmap)Bitmap.FromFile(ListinputFileName[i]);
            }
            Bitmap converted = new Bitmap(bmpIn.Width, bmpIn.Height, PixelFormat.Format24bppRgb);
            using (Graphics g = Graphics.FromImage(converted))
            {
                g.PageUnit = GraphicsUnit.Pixel;
                g.DrawImageUnscaled(bmpIn, 0, 0);
            }
            ConvertedBitmaps.Add(converted);
            return ConvertedBitmaps;
        }

List<String> giffiles = Directory.GetFiles(radarImagesDirectory, "*.gif")
                                     .Select(path => Path.GetFileName(path))
                                     .ToList();
testfiles.AddRange(giffiles);
testfiles = testfiles.OrderBy(q => q).ToList();