C# TreeView 磁盤文件，資源管理器，AfterSelect，顯示加號

可以看到，項的前面都顯示了加號(+),而且讀取了磁盤的文件。代碼如下
主程序代碼：
[csharp]
<span style="font-size:14px;">using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Windows.Forms; 
using System.IO; 
namespace FileManager 
{ 
    public partial class Main : Form 
    { 
        public Main() 
        { 
            InitializeComponent(); 
        } 
        /// <summary> 
        /// 加載邏輯磁盤文件 
        /// </summary> 
        /// <param name="sender"></param> 
        /// <param name="e"></param> 
        private void Main_Load(object sender, EventArgs e) 
        { 
            DriveInfo[] myDrivers = DriveInfo.GetDrives(); 
            foreach (DriveInfo di in myDrivers) 
            { 
                if (di.IsReady) 
                { 
                    TreeNode tNode = new TreeNode(di.Name.Split(':')[0]); 
                    tNode.Name = di.Name; 
                    tNode.Tag = tNode.Name; 
                    <span style="color:#ff0000;">tNode</span>.<span style="color:#ff0000;">Nodes</span>.<span style="color:#ff0000;">Add</span><span style="color:#ff0000;">("</span><span style="color:#ff0000;">DUMMY</span><span style="color:#ff0000;">");</span> 
                    tvRoot.Nodes.Add(tNode); 
                } 
            } 
            //添加鼠標右鍵的事件 
            this.tvRoot.ContextMenuStrip = new TreeViewContextMenu().Load(); 
        } 
 
        /// <summary> 
        /// TreeView必須處理的兩個事件之一 
        /// </summary> 
        /// <param name="sender"></param> 
        /// <param name="e"></param> 
        private void tvRoot_AfterSelect(object sender, TreeViewEventArgs e) 
        { 
            e.Node.Expand(); 
        } 
 
        /// <summary> 
        /// TreeView必須處理的兩個事件之一 
        /// </summary> 
        /// <param name="sender"></param> 
        /// <param name="e"></param> 
        private void tvRoot_BeforeExpand(object sender, TreeViewCancelEventArgs e) 
        { 
            TreeViewItems.Add(sender, e); 
        } 
    } 
}</span> 

為TreeView添加TreeNode的代碼：
[csharp] 
<span style="font-size:14px;">public static  class TreeViewItems 
    { 
       public static void Add(object sender, TreeViewCancelEventArgs e) 
       { 
           e.Node.Nodes.Clear(); 
           TreeNode tNode = e.Node; 
           //MessageBox.Show(tNode.Name); 
           string path = tNode.Name; 
           string[] dics = Directory.GetDirectories(path); 
           foreach (string dic in dics) 
           { 
               TreeNode subNode = new TreeNode(new DirectoryInfo(dic).Name); 
               subNode.Name = new DirectoryInfo(dic).FullName; 
               subNode.Tag = subNode.Name; 
               <span style="color:#ff0000;">subNode</span>.<span style="color:#ff0000;">Nodes</span>.<span style="color:#ff6666;">Add</span><span style="color:#ff0000;">("");</span> 
               tNode.Nodes.Add(subNode); 
 
           } 
           string[] files = Directory.GetFiles(path); 
           foreach (string aFile in files) 
           { 
               TreeNode subNode = new TreeNode(new FileInfo(aFile).Name); 
               subNode.Tag = aFile; 
               subNode.Name = subNode.Text; 
               tNode.Nodes.Add(subNode); 
           } 
       } 
    }</span> 

這裡注意e.Node.Nodes.Clear();還有給節點的下面添加一個空的節點：如
tNode.Nodes.Add("DUMMY");
和
subNode.Nodes.Add("");
這些都是添加空節點的方式來顯示 “加號”。。。然後正式加載的時候刪掉