C#获取文件超大图标256*256(转）

从Bing搜索得到，保存于此

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Media.Imaging;
using System.Windows.Media;
using System.Diagnostics;

namespace WpfApplication1
{
    public class c_icon_of_path
    {
        private struct RECT
        {
            public int Left;
            public int Top;
            public int Right;
            public int Bottom;
        }
        private struct POINT
        {
            public int x;
            public int y;
        }
        // Constants that we need in the function call

        private const int SHGFI_ICON = 0x100;

        private const int SHGFI_SMALLICON = 0x1;

        private const int SHGFI_LARGEICON = 0x0;

        private const int SHIL_JUMBO = 0x4;
        private const int SHIL_EXTRALARGE = 0x2;

        // This structure will contain information about the file

        public struct SHFILEINFO
        {

            // Handle to the icon representing the file

            public IntPtr hIcon;

            // Index of the icon within the image list

            public int iIcon;

            // Various attributes of the file

            public uint dwAttributes;

            // Path to the file

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = )]

            public string szDisplayName;

            // File type

            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = )]

            public string szTypeName;

        };

        [System.Runtime.InteropServices.DllImport("Kernel32.dll")]
        public static extern Boolean CloseHandle(IntPtr handle);

        private struct IMAGELISTDRAWPARAMS
        {
            public int cbSize;
            public IntPtr himl;
            public int i;
            public IntPtr hdcDst;
            public int x;
            public int y;
            public int cx;
            public int cy;
            public int xBitmap;        // x offest from the upperleft of bitmap
            public int yBitmap;        // y offset from the upperleft of bitmap
            public int rgbBk;
            public int rgbFg;
            public int fStyle;
            public int dwRop;
            public int fState;
            public int Frame;
            public int crEffect;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct IMAGEINFO
        {
            public IntPtr hbmImage;
            public IntPtr hbmMask;
            public int Unused1;
            public int Unused2;
            public RECT rcImage;
        }

        #region Private ImageList COM Interop (XP)
        [ComImportAttribute()]
        [GuidAttribute("46EB5926-582E-4017-9FDF-E8998DAA0950")]
        [InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
        //helpstring("Image List"),
        interface IImageList
        {
            [PreserveSig]
            int Add(
                IntPtr hbmImage,
                IntPtr hbmMask,
                ref int pi);

            [PreserveSig]
            int ReplaceIcon(
                int i,
                IntPtr hicon,
                ref int pi);

            [PreserveSig]
            int SetOverlayImage(
                int iImage,
                int iOverlay);

            [PreserveSig]
            int Replace(
                int i,
                IntPtr hbmImage,
                IntPtr hbmMask);

            [PreserveSig]
            int AddMasked(
                IntPtr hbmImage,
                int crMask,
                ref int pi);

            [PreserveSig]
            int Draw(
                ref IMAGELISTDRAWPARAMS pimldp);

            [PreserveSig]
            int Remove(
            int i);

            [PreserveSig]
            int GetIcon(
                int i,
                int flags,
                ref IntPtr picon);

            [PreserveSig]
            int GetImageInfo(
                int i,
                ref IMAGEINFO pImageInfo);

            [PreserveSig]
            int Copy(
                int iDst,
                IImageList punkSrc,
                int iSrc,
                int uFlags);

            [PreserveSig]
            int Merge(
                int i1,
                IImageList punk2,
                int i2,
                int dx,
                int dy,
                ref Guid riid,
                ref IntPtr ppv);

            [PreserveSig]
            int Clone(
                ref Guid riid,
                ref IntPtr ppv);

            [PreserveSig]
            int GetImageRect(
                int i,
                ref RECT prc);

            [PreserveSig]
            int GetIconSize(
                ref int cx,
                ref int cy);

            [PreserveSig]
            int SetIconSize(
                int cx,
                int cy);

            [PreserveSig]
            int GetImageCount(
            ref int pi);

            [PreserveSig]
            int SetImageCount(
                int uNewCount);

            [PreserveSig]
            int SetBkColor(
                int clrBk,
                ref int pclr);

            [PreserveSig]
            int GetBkColor(
                ref int pclr);

            [PreserveSig]
            int BeginDrag(
                int iTrack,
                int dxHotspot,
                int dyHotspot);

            [PreserveSig]
            int EndDrag();

            [PreserveSig]
            int DragEnter(
                IntPtr hwndLock,
                int x,
                int y);

            [PreserveSig]
            int DragLeave(
                IntPtr hwndLock);

            [PreserveSig]
            int DragMove(
                int x,
                int y);

            [PreserveSig]
            int SetDragCursorImage(
                ref IImageList punk,
                int iDrag,
                int dxHotspot,
                int dyHotspot);

            [PreserveSig]
            int DragShowNolock(
                int fShow);

            [PreserveSig]
            int GetDragImage(
                ref POINT ppt,
                ref POINT pptHotspot,
                ref Guid riid,
                ref IntPtr ppv);

            [PreserveSig]
            int GetItemFlags(
                int i,
                ref int dwFlags);

            [PreserveSig]
            int GetOverlayImage(
                int iOverlay,
                ref int piIndex);
        };
        #endregion

        ///
        /// SHGetImageList is not exported correctly in XP.  See KB316931
        /// http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q316931
        /// Apparently (and hopefully) ordinal 727 isn't going to change.
        ///
        [DllImport("shell32.dll", EntryPoint = "#727")]
        private extern static int SHGetImageList(
            int iImageList,
            ref Guid riid,
            out IImageList ppv
            );

        // The signature of SHGetFileInfo (located in Shell32.dll)
        [DllImport("Shell32.dll")]
        public static extern int SHGetFileInfo(string pszPath, int dwFileAttributes, ref SHFILEINFO psfi, int cbFileInfo, uint uFlags);

        [DllImport("Shell32.dll")]
        public static extern int SHGetFileInfo(IntPtr pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, int cbFileInfo, uint uFlags);

        [DllImport("shell32.dll", SetLastError = true)]
        static extern int SHGetSpecialFolderLocation(IntPtr hwndOwner, Int32 nFolder,
                 ref IntPtr ppidl);

        [DllImport("user32")]
        public static extern int DestroyIcon(IntPtr hIcon);

        public struct pair
        {
            public System.Drawing.Icon icon { get; set; }
            public IntPtr iconHandleToDestroy { set; get; }

        }

        public static int DestroyIcon2(IntPtr hIcon)
        {
            return DestroyIcon(hIcon);
        }

        private static BitmapSource bitmap_source_of_icon(System.Drawing.Icon ic)
        {
            var ic2 = System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(ic.Handle,
                                                    System.Windows.Int32Rect.Empty,
                                                    System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
            ic2.Freeze();
            return ((BitmapSource)ic2);
        }

        //public static BitmapSource SystemIcon(bool small, ShellLib.ShellApi.CSIDL csidl)
        //{

        //    IntPtr pidlTrash = IntPtr.Zero;
        //    int hr = SHGetSpecialFolderLocation(IntPtr.Zero, (int)csidl, ref pidlTrash);
        //    Debug.Assert(hr == 0);

        //    SHFILEINFO shinfo = new SHFILEINFO();

        //    uint SHGFI_USEFILEATTRIBUTES = 0x000000010;

        //    // Get a handle to the large icon
        //    uint flags;
        //    uint SHGFI_PIDL = 0x000000008;
        //    if (!small)
        //    {
        //        flags = SHGFI_PIDL | SHGFI_ICON | SHGFI_LARGEICON | SHGFI_USEFILEATTRIBUTES;
        //    }
        //    else
        //    {
        //        flags = SHGFI_PIDL | SHGFI_ICON | SHGFI_SMALLICON | SHGFI_USEFILEATTRIBUTES;
        //    }

        //    var res = SHGetFileInfo(pidlTrash, 0, ref shinfo, Marshal.SizeOf(shinfo), flags);
        //    Debug.Assert(res != 0);

        //    var myIcon = System.Drawing.Icon.FromHandle(shinfo.hIcon);
        //    Marshal.FreeCoTaskMem(pidlTrash);
        //    var bs = bitmap_source_of_icon(myIcon);
        //    myIcon.Dispose();
        //    bs.Freeze(); // importantissimo se no fa memory leak
        //    DestroyIcon(shinfo.hIcon);
        //    CloseHandle(shinfo.hIcon);
        //    return bs;

        //}

        public static BitmapSource icon_of_path(string FileName, bool small, bool checkDisk, bool addOverlay)
        {
            SHFILEINFO shinfo = new SHFILEINFO();

            uint SHGFI_USEFILEATTRIBUTES = 0x000000010;
            uint SHGFI_LINKOVERLAY = 0x000008000;

            uint flags;
            if (small)
            {
                flags = SHGFI_ICON | SHGFI_SMALLICON;
            }
            else
            {
                flags = SHGFI_ICON | SHGFI_LARGEICON;
            }
            if (!checkDisk)
                flags |= SHGFI_USEFILEATTRIBUTES;
            if (addOverlay)
                flags |= SHGFI_LINKOVERLAY;

            var res = SHGetFileInfo(FileName, , ref shinfo, Marshal.SizeOf(shinfo), flags);
            if (res == )
            {
                throw (new System.IO.FileNotFoundException());
            }

            var myIcon = System.Drawing.Icon.FromHandle(shinfo.hIcon);

            var bs = bitmap_source_of_icon(myIcon);
            myIcon.Dispose();
            bs.Freeze(); // importantissimo se no fa memory leak
            DestroyIcon(shinfo.hIcon);
            CloseHandle(shinfo.hIcon);
            return bs;

        }

        public static BitmapSource icon_of_path_large(string FileName, bool jumbo, bool checkDisk)
        {

            SHFILEINFO shinfo = new SHFILEINFO();

            uint SHGFI_USEFILEATTRIBUTES = 0x000000010;
            uint SHGFI_SYSICONINDEX = 0x4000;

            int FILE_ATTRIBUTE_NORMAL = 0x80;

            uint flags;
            flags = SHGFI_SYSICONINDEX;

            if (!checkDisk)  // This does not seem to work. If I try it, a folder icon is always returned.
                flags |= SHGFI_USEFILEATTRIBUTES;

            var res = SHGetFileInfo(FileName, FILE_ATTRIBUTE_NORMAL, ref shinfo, Marshal.SizeOf(shinfo), flags);
            if (res == )
            {
                throw (new System.IO.FileNotFoundException());
            }
            var iconIndex = shinfo.iIcon;

            // Get the System IImageList object from the Shell:
            Guid iidImageList = new Guid("46EB5926-582E-4017-9FDF-E8998DAA0950");

            IImageList iml;
            int size = jumbo ? SHIL_JUMBO : SHIL_EXTRALARGE;
            var hres = SHGetImageList(size, ref iidImageList, out  iml); // writes iml
            //if (hres == 0)
            //{
            //    throw (new System.Exception("Error SHGetImageList"));
            //}

            IntPtr hIcon = IntPtr.Zero;
            int ILD_TRANSPARENT = ;
            hres = iml.GetIcon(iconIndex, ILD_TRANSPARENT, ref hIcon);
            //if (hres == 0)
            //{
            //    throw (new System.Exception("Error iml.GetIcon"));
            //}

            var myIcon = System.Drawing.Icon.FromHandle(hIcon);
            var bs = bitmap_source_of_icon(myIcon);
            myIcon.Dispose();
            bs.Freeze(); // very important to avoid memory leak
            DestroyIcon(hIcon);
            //CloseHandle(hIcon);

            return bs;

        }
    }
}