private void Form1_Load(object sender, EventArgs e)
    {
      createDrivers();//調(diào)用下面的函數(shù)
    }
    private void createDrivers()
    {
      DirectoryInfo di;
      TreeNode tn;
      string s;
      foreach (string ss in Environment.GetLogicalDrives())
      {
        /**
         * ss的值形式如下：
         * C:\
         * D:\
         * E:\
         * F:\
         * I:\
         */
        di = new DirectoryInfo(ss); //生成路徑
        if (di.Exists) //如果當(dāng)前路徑存在
        {
          s = ss.Substring(0, ss.IndexOf("\\")); //去掉路徑的 \ 得到如：C:
          tn = new TreeNode(ss); //設(shè)置結(jié)點(diǎn)的值
          tn.Tag = "Root";
      treeView1.Nodes.Add(tn); //把結(jié)點(diǎn)加入到TreeView中
     }
  }
}

private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
    {
      TreeNode tn = e.Node; //得到發(fā)生選擇事件的結(jié)點(diǎn)
      path = tn.FullPath;  //得到完整的路徑 path是一個(gè)定義的全局變量
      textBox1.Text = path; //在左上角的文本框顯示完整的路徑
      if (tn.Tag.ToString() == "File") //如果當(dāng)前結(jié)點(diǎn)是文件
      {
        string ext = path.Substring(path.LastIndexOf(".") + 1); //得到文件的后綴
        ext = ext.ToLower();
        if (ext == "ico" || ext == "gif" || ext == "jpg" || ext == "png" || ext == "bmp") //如果是圖片，設(shè)置到右邊的pictureBox
          pictureBox1.Image = Image.FromFile(path);
        else //否則使用系統(tǒng)默認(rèn)的工具打開該文件
          System.Diagnostics.Process.Start(path);
      }
      else //反之當(dāng)前結(jié)點(diǎn)是文件夾
      {
        getSubContents(tn);//得到當(dāng)前結(jié)點(diǎn)的全部內(nèi)容
      }
    }

    private void getSubContents(TreeNode parent)
    {
      DirectoryInfo di;
      TreeNode tn;
      di = new DirectoryInfo(parent.FullPath + "\\"); //得到路徑
      if (!di.Exists) return;             //路徑不存在，直接返回
      foreach (DirectoryInfo d in di.GetDirectories()) //該路徑下面的所有 文件夾
      {
        tn = new TreeNode(d.Name);
        tn.Tag = "Directory";
        parent.Nodes.Add(tn); //將該節(jié)點(diǎn)添加到父節(jié)點(diǎn)
      }
      foreach (FileInfo f in di.GetFiles())
      {
        tn = new TreeNode(f.Name); //該路徑下的所有 文件
        tn.Tag = "File";
        parent.Nodes.Add(tn);
      }
      treeNode = parent;// 全局變量 記錄當(dāng)前結(jié)點(diǎn)
    }

private void button1_Click(object sender, EventArgs e)
    {
      DirectoryInfo di = new DirectoryInfo(path + "\\");

      int p = path.LastIndexOf("\\");
      if (p >= 0)
      {
        path = path.Substring(0, p);
        textBox1.Text = path;
        if (treeNode != null) {             //全局變量 當(dāng)前選中的結(jié)點(diǎn)

          treeNode.Nodes.Clear();           //移除當(dāng)前結(jié)點(diǎn)下的所有子節(jié)點(diǎn)
          treeView1.SelectedNode = treeNode.Parent;  //設(shè)置他的父節(jié)點(diǎn)為當(dāng)前選中結(jié)點(diǎn)
        }
      }
    }