c# - 从 Windows 移动应用程序获取文件的图标

Question

我正在使用 C# 为 windows mobible 6 开发应用程序。我需要获取文件的图标，但我不知道该怎么做 =P。

有没有办法得到它？

Answer 1

是的，虽然它不是无痛的，并且需要使用 PInvoke。这是我的做法。（WinApi是一个辅助静态类，其中包含 PInvoke 外部函数定义以及一些必需的常量。其中还有更多内容，但我删除了与获取文件图标无关的内容。）

using System;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Drawing;

namespace ExtendedCF {
    public static class WinApi
    {
        #region Icons
        [DllImport("coredll.dll")]
        public static extern bool DestroyIcon(IntPtr hIcon);
        #endregion

        #region SHGetFileInfo
        [DllImport("coredll.dll", CharSet = CharSet.Auto)]
        public static extern int SHGetFileInfo(
          string pszPath,
          int dwFileAttributes,
          out SHFILEINFO psfi,
          uint cbfileInfo,
          SHGFI uFlags);

        [Flags]
        public enum SHGFI : int
        {
            /// <summary>get icon</summary>
            Icon = 0x000000100,
            /// <summary>get display name</summary>
            DisplayName = 0x000000200,
            /// <summary>get type name</summary>
            TypeName = 0x000000400,
            /// <summary>get attributes</summary>
            Attributes = 0x000000800,
            /// <summary>get icon location</summary>
            IconLocation = 0x000001000,
            /// <summary>return exe type</summary>
            ExeType = 0x000002000,
            /// <summary>get system icon index</summary>
            SysIconIndex = 0x000004000,
            /// <summary>put a link overlay on icon</summary>
            LinkOverlay = 0x000008000,
            /// <summary>show icon in selected state</summary>
            Selected = 0x000010000,
            /// <summary>get only specified attributes</summary>
            Attr_Specified = 0x000020000,
            /// <summary>get large icon</summary>
            LargeIcon = 0x000000000,
            /// <summary>get small icon</summary>
            SmallIcon = 0x000000001,
            /// <summary>get open icon</summary>
            OpenIcon = 0x000000002,
            /// <summary>get shell size icon</summary>
            ShellIconSize = 0x000000004,
            /// <summary>pszPath is a pidl</summary>
            PIDL = 0x000000008,
            /// <summary>use passed dwFileAttribute</summary>
            UseFileAttributes = 0x000000010,
            /// <summary>apply the appropriate overlays</summary>
            AddOverlays = 0x000000020,
            /// <summary>Get the index of the overlay in the upper 8 bits of the iIcon</summary>
            OverlayIndex = 0x000000040,
        }

        /// <summary>Maximal Length of unmanaged Windows-Path-strings</summary>
        private const int MAX_PATH = 260;
        /// <summary>Maximal Length of unmanaged Typename</summary>
        private const int MAX_TYPE = 80;

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct SHFILEINFO
        {
            public SHFILEINFO(bool dummy)
            {
                hIcon = IntPtr.Zero;
                iIcon = 0;
                dwAttributes = 0;
                szDisplayName = "";
                szTypeName = "";
            }
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_PATH)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_TYPE)]
            public string szTypeName;
        };

        #endregion
    }
    public static class Utils
    {
        #region GetFileIcon and GetFolderIcon
        /// <summary>
        /// Get the associated Icon for a file or application.  Always returns
        /// an icon.  If the filePath is invalid, the default icon for files of such type is returned.
        /// </summary>
        /// <param name="filePath">full path to the file</param>
        /// <param name="bSmall">if true, return the 16x16 icon; otherwise, the 32x32 icon</param>
        /// <returns></returns>
        private static Icon GetIcon(string filePath, bool bFolder, bool bSmall)
        {
            WinApi.SHFILEINFO info = new WinApi.SHFILEINFO(true);
            int cbFileInfo = Marshal.SizeOf(info);
            WinApi.SHGFI flags = WinApi.SHGFI.Icon | WinApi.SHGFI.UseFileAttributes;
            if (bSmall)
                flags |= WinApi.SHGFI.SmallIcon;
            else
                flags |= WinApi.SHGFI.LargeIcon;

            int fileAttributes = 0;
            if (bFolder)
            {
                fileAttributes = (int)FileAttributes.Directory;
            }

            WinApi.SHGetFileInfo(filePath, fileAttributes, out info, (uint)cbFileInfo, flags);
            Icon rv = (Icon)Icon.FromHandle(info.hIcon).Clone();
            WinApi.DestroyIcon(info.hIcon);
            return rv;
        }
        private static Icon GetIcon(string filePath, bool bFolder)
        {
            return GetIcon(filePath, bFolder, false);
        }
        public static Icon GetFileIcon(string filePath)
        {
            return GetIcon(filePath, false);
        }
        public static Icon GetFolderIcon(string folderPath)
        {
            return GetIcon(folderPath, true);
        }
        public static Icon GetFileIcon(string filePath, bool bSmall)
        {
            return GetIcon(filePath, false, bSmall);
        }
        public static Icon GetFolderIcon(string folderPath, bool bSmall)
        {
            return GetIcon(folderPath, true, bSmall);
        }
        #endregion
    }
}