var fullPath = @"C:\folder1\folder2\file.txt";
var lastDirectory = Path.GetDirectoryName(fullPath).Split('\\').LastOrDefault();

试试这个:

string filename = @"C:/folder1/folder2/file.txt";
string FolderName = new DirectoryInfo(System.IO.Path.GetDirectoryName(filename)).Name;

DirectoryInfo执行剥离目录名的工作

string my_path = @"C:\Windows\System32";
DirectoryInfo dir_info = new DirectoryInfo(my_path);
string directory = dir_info.Name;  // System32

下面的代码只帮助获取文件夹名称

 public ObservableCollection items = new ObservableCollection();

   try
            {
                string[] folderPaths = Directory.GetDirectories(stemp);
                items.Clear();
                foreach (string s in folderPaths)
                {
                    items.Add(new gridItems { foldername = s.Remove(0, s.LastIndexOf('\\') + 1), folderpath = s });

                }

            }
            catch (Exception a)
            {

            }
  public class gridItems
    {
        public string foldername { get; set; }
        public string folderpath { get; set; }
    }

string Folder = Directory.GetParent(path).Name;

var fullPath = @"C:\folder1\folder2\file.txt";
var lastDirectory = Path.GetDirectoryName(fullPath).Split('\\').LastOrDefault();