c#用Treeview实现FolderBrowerDialog和动态获取系统图标（运用了Win32dll类库）

public MyDirectory()
      {
          InitializeComponent();
          treeViewDirectory.BeginUpdate();
          label1.Text = folderTitle;
          treeViewDirectory.ImageList = imageList1;
          treeViewDirectory.SelectedImageIndex = 3;
          EnumDrivers();
          treeViewDirectory.EndUpdate();

          this.SetBounds((Screen.GetBounds(this).Width / 2) - (this.Width / 2), (Screen.GetBounds(this).Height / 2) - (this.Height / 2), this.Width, this.Height, BoundsSpecified.Location);
      }
      public static string folderTitle = "";
      private void EnumDrivers()
      {
          //treeViewDirectory.ImageIndex = 1;
          string[] allDriveNames = Directory.GetLogicalDrives();
          TreeNode rootNode = new TreeNode();
          rootNode.Text = "My Computer";
          rootNode.ImageIndex = 1;
          rootNode.Expand();
          treeViewDirectory.Nodes.Add(rootNode);
          treeViewDirectory.SelectedNode = rootNode.FirstNode;
          DriveInfo[] allDrives = DriveInfo.GetDrives();
          int j = 0;
          try
          {
              int i = 0;
              foreach (DriveInfo d in allDrives)
              {
                  TreeNode tn = new TreeNode(d.Name);

                  // GetIcon(d.Name, false)
                  this.imageList1.Images.Add(GetIcon(d.Name, false));

                  tn.ImageIndex = 2;

                  tn.Tag = d.RootDirectory.FullName;
                  treeViewDirectory.Nodes[0].Nodes.Add(tn);
                   treeViewDirectory.Nodes[0].Nodes[j].Text = d.Name ;
                  ShowDirs(tn);
                  j++;
              }
          }
          catch (System.Exception)
          {
          }
      }

      private void ShowDirs(TreeNode tn)
      {
          tn.Nodes.Clear();
          try
          {
              DirectoryInfo DirInfo = new DirectoryInfo(tn.Tag.ToString());
              if (!DirInfo.Exists)
              {
                  return;
              }
              else
              {
                  DirectoryInfo[] Dirs;
                  try
                  {
                      Dirs = DirInfo.GetDirectories();
                  }
                  catch (Exception e)
                  {
                      return;
                  }
                  foreach (DirectoryInfo Dir in Dirs)
                  {
                      TreeNode dir = new TreeNode(Dir.Name);
                      dir.ImageIndex = 0;
                      dir.Tag = Dir.FullName;
                      tn.Nodes.Add(dir);
                  }
              }
          }
          catch (System.Exception)
          { }
      }

      private void treeViewDirectory_BeforeExpand(object sender, TreeViewCancelEventArgs e)
      {
          treeViewDirectory.BeginUpdate();
          foreach (TreeNode tn in e.Node.Nodes)
          {
              ShowDirs(tn);
          }
          treeViewDirectory.EndUpdate();
      }

      public static string myValue { set; get; }
      private void btnOK_Click(object sender, EventArgs e)
      {
          MyDirectory.myValue = lastResult;
          this.Close();
      }

      private void btnCancel_Click(object sender, EventArgs e)
      {
          MyDirectory.myValue = null;
          this.Close();
      }
      private static string lastResult = null;
      private void treeViewDirectory_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
      {
          lastResult = null;
          string result = e.Node.FullPath;
          if (result != "My Computer")
          {
              if (result.Contains(@"My Computer\") || result.Contains("My Computer"))
              {
                  int len = 0;
                  if (result.Contains(@"My Computer\"))
                  {
                      len = @"My Computer\".Length;
                  }
                  else
                  {
                      len = "My Computer".Length;
                  }
                  result = result.Substring(len);
return result;
              }
          }
      }

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Runtime.InteropServices;

namespace HP.DMT.UI
{
    public partial class MyDirectory : Form
    {

        public MyDirectory()
        {
            InitializeComponent();
            treeViewDirectory.BeginUpdate();
            label1.Text = folderTitle;
            treeViewDirectory.ImageList = imageList1;
            treeViewDirectory.SelectedImageIndex = 3;
            EnumDrivers();
            treeViewDirectory.EndUpdate();

            this.SetBounds((Screen.GetBounds(this).Width / 2) - (this.Width / 2), (Screen.GetBounds(this).Height / 2) - (this.Height / 2), this.Width, this.Height, BoundsSpecified.Location);
        }
        public static string folderTitle = "";
        private void EnumDrivers()
        {
            //treeViewDirectory.ImageIndex = 1;
            string[] allDriveNames = Directory.GetLogicalDrives();
            TreeNode rootNode = new TreeNode();
            rootNode.Text = "My Computer";
            rootNode.ImageIndex = 1;
            rootNode.Expand();
            treeViewDirectory.Nodes.Add(rootNode);
            treeViewDirectory.SelectedNode = rootNode.FirstNode;
            DriveInfo[] allDrives = DriveInfo.GetDrives();
            int j = 0;
            try
            {
                int i = 0;
                foreach (DriveInfo d in allDrives)
                {
                    TreeNode tn = new TreeNode(d.Name);

                    // GetIcon(d.Name, false)
                    this.imageList1.Images.Add(GetIcon(d.Name, false));

                    tn.ImageIndex = 4 + i;
                    i++;
                    tn.Tag = d.RootDirectory.FullName;
                    treeViewDirectory.Nodes[0].Nodes.Add(tn);
                    if (d.DriveType.ToString() == "Fixed")
                    {
                        treeViewDirectory.Nodes[0].Nodes[j].Text = d.Name + "(" + d.DriveType.ToString() + "," + d.TotalFreeSpace / 1024 / 1024 / 1024 + "G/" + d.TotalSize / 1024 / 1024 / 1024 + "G)";
                    }
                    else
                    {
                        treeViewDirectory.Nodes[0].Nodes[j].Text = d.Name + "(" + d.DriveType.ToString() + ")";
                    }
                    ShowDirs(tn);
                    j++;
                }
            }
            catch (System.Exception)
            {
            }
        }

        private void ShowDirs(TreeNode tn)
        {
            tn.Nodes.Clear();
            try
            {
                DirectoryInfo DirInfo = new DirectoryInfo(tn.Tag.ToString());
                if (!DirInfo.Exists)
                {
                    return;
                }
                else
                {
                    DirectoryInfo[] Dirs;
                    try
                    {
                        Dirs = DirInfo.GetDirectories();
                    }
                    catch (Exception e)
                    {
                        return;
                    }
                    foreach (DirectoryInfo Dir in Dirs)
                    {
                        TreeNode dir = new TreeNode(Dir.Name);
                        dir.ImageIndex = 0;
                        dir.Tag = Dir.FullName;
                        tn.Nodes.Add(dir);
                    }
                }
            }
            catch (System.Exception)
            { }
        }

        private void treeViewDirectory_BeforeExpand(object sender, TreeViewCancelEventArgs e)
        {
            treeViewDirectory.BeginUpdate();
            foreach (TreeNode tn in e.Node.Nodes)
            {
                ShowDirs(tn);
            }
            treeViewDirectory.EndUpdate();
        }

        public static string myValue { set; get; }
        private void btnOK_Click(object sender, EventArgs e)
        {
            MyDirectory.myValue = lastResult;
            this.Close();
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            MyDirectory.myValue = null;
            this.Close();
        }
        private static string lastResult = null;
        private void treeViewDirectory_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
        {
            lastResult = null;
            string result = e.Node.FullPath;
            if (result != "My Computer")
            {
                if (result.Contains(@"My Computer\") || result.Contains("My Computer"))
                {
                    int len = 0;
                    if (result.Contains(@"My Computer\"))
                    {
                        len = @"My Computer\".Length;
                    }
                    else
                    {
                        len = "My Computer".Length;
                    }
                    result = result.Substring(len);

                    char[] arrs = result.ToCharArray();
                    int beforLenth = result.Remove(result.IndexOf('/') + 1).Length;
                    int afterLenth = result.Substring(result.IndexOf('/') + 1).Remove(result.Substring(result.IndexOf('/') + 1).IndexOf(')')).Length;

                    char[] c = { ')' };
                    string str1 = result.Substring(0, 3);
                    string str2 = result.Substring(result.IndexOfAny(c, beforLenth + afterLenth, 1) + 1);

                    lastResult = str1 + str2;
                }
            }
        }

 
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct SHFILEINFO
        {
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeCOnst= 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeCOnst= 80)]
            public string szTypeName;
        }

        [DllImport("Shell32.dll", EntryPoint = "SHGetFileInfo", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbFileInfo, uint uFlags);

        [DllImport("User32.dll", EntryPoint = "DestroyIcon")]
        public static extern int DestroyIcon(IntPtr hIcon);

 
        public const uint SHGFI_ICON = 0x100;
        public const uint SHGFI_LARGEICON = 0x0;
        public const uint SHGFI_SMALLICON = 0x1;
        public const uint SHGFI_USEFILEATTRIBUTES = 0x10;

        static Icon GetIcon(string fileName, bool isLargeIcon)
        {
            SHFILEINFO shfi = new SHFILEINFO();
            IntPtr hI;

            if (isLargeIcon)
                hI = MyDirectory.SHGetFileInfo(fileName, 0, ref shfi,
                     (uint)Marshal.SizeOf(shfi), MyDirectory.SHGFI_ICON | MyDirectory.SHGFI_USEFILEATTRIBUTES | MyDirectory.SHGFI_LARGEICON);
            else
                hI = MyDirectory.SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), MyDirectory.SHGFI_ICON | MyDirectory.SHGFI_USEFILEATTRIBUTES | MyDirectory.SHGFI_SMALLICON);
            Icon icon = Icon.FromHandle(shfi.hIcon).Clone() as Icon;
            MyDirectory.DestroyIcon(shfi.hIcon);
            return icon;
        }
    }
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct SHFILEINFO
        {
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeCOnst= 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeCOnst= 80)]
            public string szTypeName;
        }

        [DllImport("Shell32.dll", EntryPoint = "SHGetFileInfo", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbFileInfo, uint uFlags);

        [DllImport("User32.dll", EntryPoint = "DestroyIcon")]
        public static extern int DestroyIcon(IntPtr hIcon);

 
        public const uint SHGFI_ICON = 0x100;
        public const uint SHGFI_LARGEICON = 0x0;
        public const uint SHGFI_SMALLICON = 0x1;
        public const uint SHGFI_USEFILEATTRIBUTES = 0x10;

        static Icon GetIcon(string fileName, bool isLargeIcon)
        {
            SHFILEINFO shfi = new SHFILEINFO();
            IntPtr hI;

            if (isLargeIcon)
                hI = MyDirectory.SHGetFileInfo(fileName, 0, ref shfi,
                     (uint)Marshal.SizeOf(shfi), MyDirectory.SHGFI_ICON | MyDirectory.SHGFI_USEFILEATTRIBUTES | MyDirectory.SHGFI_LARGEICON);
            else
                hI = MyDirectory.SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), MyDirectory.SHGFI_ICON | MyDirectory.SHGFI_USEFILEATTRIBUTES | MyDirectory.SHGFI_SMALLICON);
            Icon icon = Icon.FromHandle(shfi.hIcon).Clone() as Icon;
            MyDirectory.DestroyIcon(shfi.hIcon);
            return icon;
        }