(C#)把磁盘目录树加载在窗体菜单中

这又是一个没有技术含量的代码。写出来只是玩玩，所以也不敢放在首页。



这里有个问题，是获取文件/文件夹的图标。使用 System.Drawing.Icon.ExtractAssociatedIcon 只能获取大图标（不知道有没有高手能做到取小图标）。所以只能使用API了。设计一个这样的 ExtractIcon 类，提供一个静态方法 GetIcon ，用于获取小图标：

ExtractIcon.cs
using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Drawing;

namespace FileMenu
{
    public class ExtractIcon
    {
        [DllImport("Shell32.dll")]
        private static extern int SHGetFileInfo
          (
          string pszPath,
          uint dwFileAttributes,
          out   SHFILEINFO psfi,
          uint cbfileInfo,
          SHGFI uFlags
          );
 
        [StructLayout(LayoutKind.Sequential)]
        private struct SHFILEINFO
        {
            public SHFILEINFO(bool b)
            {
                hIcon = IntPtr.Zero; iIcon = 0; dwAttributes = 0; szDisplayName = ""; szTypeName = "";
            }
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 80)]
            public string szTypeName;
        };
 
        private ExtractIcon()
        {
        }
 
        private enum SHGFI
        {
            SmallIcon = 0x00000001,
            LargeIcon = 0x00000000,
            Icon = 0x00000100,
            DisplayName = 0x00000200,
            Typename = 0x00000400,
            SysIconIndex = 0x00004000,
            UseFileAttributes = 0x00000010
        }
 
        /**//// <summary>
        /// 获取文件、文件夹的小图标
        /// </summary>
        /// <param name="strPath">文件、文件夹路径</param>
        /// <returns>图标</returns>
        public static Icon GetIcon(string strPath)
        {
            SHFILEINFO info = new SHFILEINFO(true);
            int cbFileInfo = Marshal.SizeOf(info);
            SHGFI flags;
            flags = SHGFI.Icon | SHGFI.SmallIcon;
            SHGetFileInfo(strPath, 256, out   info, (uint)cbFileInfo, flags);
            return Icon.FromHandle(info.hIcon);
        }
    }
}

然后我们通过 ToolStripMenuItem 的 DropDownOpening 事件，加载它的子文件/文件夹。代码比较简单：

Form1.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Collections;

namespace FileMenu
{
    public partial class Form1 : Form
    {

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //加载磁盘
            string[] disks = Directory.GetLogicalDrives();
            for (int i = 0; i < disks.Length; i++)
            {
                string disk = disks[i];
                ToolStripMenuItem tsm = new ToolStripMenuItem(disk, ExtractIcon.GetIcon(disk).ToBitmap());
                tsm.Tag = disk;
                tsm.ToolTipText = disk;
                tsm.DropDownOpening += new EventHandler(ShowItem);
                mnuMain.Items.Add(tsm);
            }
        }

        //加载子菜单
        private void ShowItem(object sender, EventArgs e)
        {
            //用 tag 存储路径。如果 tag 为空，表示该菜单已经加载过。
            ToolStripMenuItem tParent = (ToolStripMenuItem)sender;
            string path = (string)tParent.Tag;
            if (string.IsNullOrEmpty(path))
            {
                return;
            }

            tParent.Tag = "";                                                                                                                                                                                  
            tParent.DropDownItems.Clear();

            DirectoryInfo parent = new DirectoryInfo(path);
            try
            {
                //先加载子文件夹
                DirectoryInfo[] dis = parent.GetDirectories();
                for (int i = 0; i < dis.Length; i++)
                {
                    DirectoryInfo di = dis[i];
                    ToolStripMenuItem tsm = new ToolStripMenuItem(di.Name, ExtractIcon.GetIcon(di.FullName).ToBitmap());
                    tsm.Tag = di.FullName;
                    tsm.ToolTipText = di.FullName;
                    tsm.DropDownOpening += new EventHandler(ShowItem);
                    tsm.Click += new EventHandler(OpenItem);

                    if (di.GetDirectories().Length > 0 || di.GetFiles().Length > 0)
                    {
                        tsm.DropDownItems.Add("");
                    }
                    else
                    {
                        tsm.Tag = "";
                    }

                    tParent.DropDownItems.Add(tsm);
                }

                //加载子文件
                FileInfo[] fis = parent.GetFiles();
                for (int j = 0; j < fis.Length; j++)
                {
                    FileInfo fi = fis[j];
                    ToolStripMenuItem tsm = new ToolStripMenuItem(fi.Name, ExtractIcon.GetIcon(fi.FullName).ToBitmap());
                    tsm.Tag = fi.FullName;
                    tsm.ToolTipText = fi.FullName;
                    tsm.Click += new EventHandler(OpenItem);
                    tParent.DropDownItems.Add(tsm);
                }
            }
            catch{ }

        }

        //打开子菜单
        private void OpenItem(object sender, EventArgs e)
        {
            ToolStripMenuItem tsm = (ToolStripMenuItem)sender;
            string path = (string)tsm.ToolTipText;
            System.Diagnostics.Process.Start(path);
        }
    }
}

源代码：/Files/lemony/FileMenu.rar