/// <summary>
        /// Used to access system folder icons.
        /// </summary>
        /// <param name="size">Specify large or small icons.</param>
        /// <param name="folderType">Specify open or closed FolderType.</param>
        /// <param name="shfi">Return Folder Information</param>
        /// <returns>System.Drawing.Icon</returns>
        public static Icon GetFolderIcon(IconSize size, FolderType folderType, ref Shell32.SHFILEINFO shfi)
        {
            // Need to add size check, although errors generated at present!
            Shell32.SHGetFileInfoConstants flags = Shell32.SHGetFileInfoConstants.SHGFI_TYPENAME | Shell32.SHGetFileInfoConstants.SHGFI_DISPLAYNAME | Shell32.SHGetFileInfoConstants.SHGFI_ICON | Shell32.SHGetFileInfoConstants.SHGFI_USEFILEATTRIBUTES;

            if (FolderType.Open == folderType)
            {
                flags |= Shell32.SHGetFileInfoConstants.SHGFI_OPENICON;
            }

            if (IconSize.Small == size)
            {
                flags |= Shell32.SHGetFileInfoConstants.SHGFI_SMALLICON;
            }
            else
            {
                flags |= Shell32.SHGetFileInfoConstants.SHGFI_LARGEICON;
            }

            IntPtr hIml;

            // Get the folder icon
            shfi = new Shell32.SHFILEINFO();
            if (IconHelper.Utils.IsSevenOrAbove()) // Windows 7 FIX
            {
                hIml = Shell32.SHGetFileInfo(Environment.GetFolderPath(Environment.SpecialFolder.System),
                                             Shell32.FILE_ATTRIBUTE.DIRECTORY,
                                             ref shfi,
                                             (uint)Marshal.SizeOf(shfi),
                                             flags);
            }
            else
            {
                hIml = Shell32.SHGetFileInfo(null,
                                             Shell32.FILE_ATTRIBUTE.DIRECTORY,
                                             ref shfi,
                                             (uint)Marshal.SizeOf(shfi),
                                             flags);
            }
            if (shfi.hIcon == IntPtr.Zero)
            {
                return(null);
            }
            if (!IconHelper.Utils.IsXpOrAbove())
            {
                return(GetManagedIcon(shfi.hIcon));
            }
            // Get the System IImageList object from the Shell:
            Guid iidImageList = new Guid("46EB5926-582E-4017-9FDF-E8998DAA0950");

            Shell32.IImageList iImageList = null;
            int ret = Shell32.SHGetImageList(
                (int)size,
                ref iidImageList,
                ref iImageList
                );

            // the image list handle is the IUnknown pointer, but
            // using Marshal.GetIUnknownForObject doesn't return
            // the right value.  It really doesn't hurt to make
            // a second call to get the handle:
            Shell32.SHGetImageListHandle((int)size, ref iidImageList, ref hIml);
            IntPtr hIcon = IntPtr.Zero;

            if (iImageList == null)
            {
                hIcon = Comctl32.ImageList_GetIcon(
                    hIml,
                    shfi.iIcon,
                    (int)Comctl32.ImageListDrawItemConstants.ILD_TRANSPARENT);
            }
            else
            {
                iImageList.GetIcon(
                    shfi.iIcon,
                    (int)Comctl32.ImageListDrawItemConstants.ILD_TRANSPARENT,
                    ref hIcon);
            }
            return(hIcon == IntPtr.Zero ? GetManagedIcon(shfi.hIcon) : GetManagedIcon(hIcon));
        }
 private static extern int SHGetImageList(
     int iImageList,
     ref Guid riid,
     out Shell32.IImageList ppv);
        /// <summary>
        /// Returns an icon for a given file - indicated by the name parameter.
        /// </summary>
        /// <param name="name">Extension or pathname for file.</param>
        /// <param name="size">Large or small</param>
        /// <param name="linkOverlay">Whether to include the link icon</param>
        /// <param name="shfi">Return File Information</param>
        /// <returns>System.Drawing.Icon</returns>
        public static Icon GetFileIcon(string name, IconSize size, bool linkOverlay, ref Shell32.SHFILEINFO shfi)
        {
            name = Environment.ExpandEnvironmentVariables(name);
            shfi = new Shell32.SHFILEINFO();
            Shell32.SHGetFileInfoConstants flags = Shell32.SHGetFileInfoConstants.SHGFI_TYPENAME | Shell32.SHGetFileInfoConstants.SHGFI_DISPLAYNAME | Shell32.SHGetFileInfoConstants.SHGFI_ICON | Shell32.SHGetFileInfoConstants.SHGFI_SHELLICONSIZE | Shell32.SHGetFileInfoConstants.SHGFI_SYSICONINDEX | Shell32.SHGetFileInfoConstants.SHGFI_USEFILEATTRIBUTES;

            if (linkOverlay)
            {
                flags |= Shell32.SHGetFileInfoConstants.SHGFI_LINKOVERLAY;
            }
            /* Check the size specified for return. */
            if (IconSize.Small == size)
            {
                flags |= Shell32.SHGetFileInfoConstants.SHGFI_SMALLICON;
            }
            else
            {
                flags |= Shell32.SHGetFileInfoConstants.SHGFI_LARGEICON;
            }

            IntPtr hIml = Shell32.SHGetFileInfo(name,
                                                Shell32.FILE_ATTRIBUTE.NORMAL,
                                                ref shfi,
                                                (uint)Marshal.SizeOf(shfi),
                                                flags);

            if (shfi.hIcon == IntPtr.Zero)
            {
                return(null);
            }
            if (!IconHelper.Utils.IsXpOrAbove())
            {
                return(GetManagedIcon(shfi.hIcon));
            }
            // Get the System IImageList object from the Shell:
            Guid iidImageList = new Guid("46EB5926-582E-4017-9FDF-E8998DAA0950");

            Shell32.IImageList iImageList = null;
            int ret = Shell32.SHGetImageList(
                (int)size,
                ref iidImageList,
                ref iImageList
                );

            // the image list handle is the IUnknown pointer, but
            // using Marshal.GetIUnknownForObject doesn't return
            // the right value.  It really doesn't hurt to make
            // a second call to get the handle:
            Shell32.SHGetImageListHandle((int)size, ref iidImageList, ref hIml);

            IntPtr hIcon = IntPtr.Zero;

            if (iImageList == null)
            {
                hIcon = Comctl32.ImageList_GetIcon(
                    hIml,
                    shfi.iIcon,
                    (int)Comctl32.ImageListDrawItemConstants.ILD_TRANSPARENT);
            }
            else
            {
                iImageList.GetIcon(
                    shfi.iIcon,
                    (int)Comctl32.ImageListDrawItemConstants.ILD_TRANSPARENT,
                    ref hIcon);
            }
            return(hIcon == IntPtr.Zero ? GetManagedIcon(shfi.hIcon) : GetManagedIcon(hIcon));
        }