如何在Treeview VS 2010 C＃中显示所有文件夹

Question

我正在尝试制作一个小型应用程序，并且需要显示所有文件夹才能选择特定的文件/文件夹。

我找到了一个较旧主题的源代码，但是它不起作用。我只能在某些地方看不到文件夹。

能请您看看并告诉我您的意见吗？

 private void Form1_Load(object sender, EventArgs e)
    {

        string[] drives = Environment.GetLogicalDrives();

        foreach (string drive in drives)
        {
            DriveInfo di = new DriveInfo(drive);
            int driveImage;

            switch (di.DriveType)    //set the drive's icon
            {
                case DriveType.CDRom:
                    driveImage = 3;
                    break;
                case DriveType.Network:
                    driveImage = 6;
                    break;
                case DriveType.NoRootDirectory:
                    driveImage = 8;
                    break;
                case DriveType.Unknown:
                    driveImage = 8;
                    break;
                default:
                    driveImage = 2;
                    break;
            }

            TreeNode node = new TreeNode(drive.Substring(0, 1), driveImage, driveImage);
            node.Tag = drive;

            if (di.IsReady == true)
                node.Nodes.Add("...");

            dirsTreeView.Nodes.Add(node);
        }



    }

    private void dirsTreeView_BeforeExpand(object sender, TreeViewCancelEventArgs e)
    {

        if (e.Node.Nodes.Count > 0)
        {
            if (e.Node.Nodes[0].Text == "..." && e.Node.Nodes[0].Tag == null)
            {
                e.Node.Nodes.Clear();

                //get the list of sub direcotires
                string[] dirs = Directory.GetDirectories(e.Node.Tag.ToString());

                //add files of rootdirectory
                DirectoryInfo rootDir = new DirectoryInfo(e.Node.Tag.ToString());
                foreach (var file in rootDir.GetFiles())
                {
                    TreeNode n = new TreeNode(file.Name, 13, 13);
                    e.Node.Nodes.Add(n);
                }

                foreach (string dir in dirs)
                {
                    DirectoryInfo di = new DirectoryInfo(dir);
                    TreeNode node = new TreeNode(di.Name, 0, 1);

                    try
                    {
                        //keep the directory's full path in the tag for use later
                        node.Tag = dir;

                        //if the directory has sub directories add the place holder
                        if (di.GetDirectories().Count() > 0)
                            node.Nodes.Add(null, "...", 0, 0);

                        foreach (var file in di.GetFiles())
                        {
                            TreeNode n = new TreeNode(file.Name, 13, 13);
                            node.Nodes.Add(n);
                        }

                    }
                    catch (UnauthorizedAccessException)
                    {
                        //display a locked folder icon
                        node.ImageIndex = 12;
                        node.SelectedImageIndex = 12;
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message, "DirectoryLister",
                            MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                    finally
                    {
                        e.Node.Nodes.Add(node);
                    }
                }
            }
        }

    }

谢谢您的支持！祝你有美好的一天！