treeView显示目录及文件

完整代码：

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.IO;
using System.Management;
using System.Text;

namespace test
{
 /// <summary>
 /// Form1 的摘要说明。
 /// </summary>
 public class Form1 : System.Windows.Forms.Form
 {
  private System.Windows.Forms.TreeView treeView1;
  /// <summary>
  /// 必需的设计器变量。
  /// </summary>
  private System.ComponentModel.Container components = null;

  public Form1()
  {
   //
   // Windows 窗体设计器支持所必需的
   //
   InitializeComponent();

   //
   // TODO: 在 InitializeComponent 调用后添加任何构造函数代码
   //
  }

  /// <summary>
  /// 清理所有正在使用的资源。
  /// </summary>
  protected override void Dispose( bool disposing )
  {
   if( disposing )
   {
    if (components != null)
    {
     components.Dispose();
    }
   }
   base.Dispose( disposing );
  }

  #region Windows 窗体设计器生成的代码
  /// <summary>
  /// 设计器支持所需的方法 - 不要使用代码编辑器修改
  /// 此方法的内容。
  /// </summary>
  private void InitializeComponent()
  {
   this.treeView1 = new System.Windows.Forms.TreeView();
   this.SuspendLayout();
   //
   // treeView1
   //
   this.treeView1.ImageIndex = -1;
   this.treeView1.Location = new System.Drawing.Point(8, 16);
   this.treeView1.Name = "treeView1";
   this.treeView1.SelectedImageIndex = -1;
   this.treeView1.Size = new System.Drawing.Size(272, 232);
   this.treeView1.TabIndex = 0;
   this.treeView1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.treeView1_MouseDown);
   this.treeView1.DoubleClick += new System.EventHandler(this.treeView1_DoubleClick);
   this.treeView1.BeforeExpand += new System.Windows.Forms.TreeViewCancelEventHandler(this.treeView1_BeforeExpand);
   //
   // Form1
   //
   this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
   this.ClientSize = new System.Drawing.Size(292, 273);
   this.Controls.Add(this.treeView1);
   this.Name = "Form1";
   this.Text = "Form1";
   this.Load += new System.EventHandler(this.Form1_Load);
   this.ResumeLayout(false);

  }
  #endregion

  /// <summary>
  /// 应用程序的主入口点。
  /// </summary>
  [STAThread]
  static void Main()
  {
   Application.Run(new Form1());
  }
  private LoadDir loadDir;
  string filter = "";
  private void Form1_Load(object sender, System.EventArgs e)
  {
   loadDir = LoadDir.CreateIntance();
   treeView1.Nodes.Add(loadDir.Drives());
  }

  private void treeView1_DoubleClick(object sender, System.EventArgs e)
  {
   if( treeView1.SelectedNode == null || treeView1.SelectedNode.Parent == null)//跟目录
    return;
   try
   {
     loadDir. ChildChildNodes(treeView1.SelectedNode,filter,true);
   }
   catch(Exception ex)
   {
    MessageBox.Show(ex.Message);
   }
  }

  private void treeView1_BeforeExpand(object sender, System.Windows.Forms.TreeViewCancelEventArgs e)
  {
   if(treeView1.SelectedNode == null || treeView1.SelectedNode.Parent == null)//跟目录
    return;
   loadDir. ChildChildNodes(e.Node,filter,true);
  }

  private void treeView1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
  {
   treeView1.SelectedNode = treeView1.GetNodeAt(e.X,e.Y);
  }
 }

 /// <summary>
 /// 加载文件目录，singleton
 /// </summary>
 public class LoadDir
 {
  private static LoadDir ld;
  private LoadDir()
  {
  }
  /// <summary>
  /// 创建实例
  /// </summary>
  /// <returns>实例</returns>
  public static LoadDir CreateIntance()
  {
   if(ld == null)
    ld = new LoadDir();
   return ld;
  }
  /// <summary>
  /// 加载磁盘列表
  /// </summary>
  /// <returns>磁盘列表树结构</returns>
  public TreeNode Drives()
  {
   TreeNode treeNode_myComp = new TreeNode("我的电脑",0,0);

   SelectQuery query=new SelectQuery("Select * From Win32_LogicalDisk");
   ManagementObjectSearcher searcher=new ManagementObjectSearcher(query);
   try
   {
    foreach(ManagementBaseObject disk in searcher.Get())
    {
     if(Convert.ToInt32(disk["DriveType"]) == 3)
     {
      TreeNode tn = new TreeNode();
      tn.Text = disk["VolumeName"].ToString()+"("+disk["Name"].ToString()+")";
      tn.Tag = disk["Name"].ToString()+"\\";
      treeNode_myComp.Nodes.Add(tn);
      ChildNodes(tn,"",false);
     }
    }
   }
   catch
   {}

   return treeNode_myComp;
  }
  /// <summary>
  /// 加载目录及文件
  /// </summary>
  /// <param name="selectedTreeNode"></param>
  /// <param name="p_filter"></param>
  /// <param name="Expand"></param>
  /// <returns></returns>
  public TreeNode ChildNodes(TreeNode selectedTreeNode,string p_filter,bool Expand)
  {
   if( File.Exists(selectedTreeNode.Tag.ToString()) != true )//目录而非文件
   {
    if( selectedTreeNode.GetNodeCount(false) <= 0 )//没打开过
    {
     try
     {
      foreach( string s in Directory.GetDirectories(selectedTreeNode.Tag.ToString()))
      {
       TreeNode tn = new TreeNode();
       tn.Tag = s;
       tn.Text = s.Split('\\')[(s.Split('\\').Length - 1)];
       selectedTreeNode.Nodes.Add(tn);
      }
      foreach( string s in Directory.GetFiles(selectedTreeNode.Tag.ToString()))
      {
       TreeNode tn = new TreeNode();
       tn.Tag = s;
       tn.Text = s.Split('\\')[(s.Split('\\').Length - 1)];
       selectedTreeNode.Nodes.Add(tn);
      }
      if(Expand == true)
       selectedTreeNode.Expand();     
     }
     catch
     {
     }
    }
   }
   return selectedTreeNode;
  }
  /// <summary>
  /// 取子级目录及文件
  /// </summary>
  /// <param name="selectedTreeNode"></param>
  /// <param name="p_filter"></param>
  /// <param name="Expand"></param>
  /// <returns></returns>
  public TreeNode ChildChildNodes(TreeNode selectedTreeNode,string p_filter,bool Expand)
  {
   try
   {
    foreach( TreeNode tn in selectedTreeNode.Nodes)
    {
     if( File.Exists(tn.Tag.ToString()) != true )//目录而非文件
     {
      ChildNodes(tn,p_filter,false);
     }
    }
   }
   catch
   {
   }
   return selectedTreeNode;
  }

  public TreeNode ChildNodes(TreeNode selectedTreeNode)
  {
   return ChildNodes(selectedTreeNode,"",false);
  }
 }
}