using SHFILEINFO to get file icons

Question

I've been searching for a c# library that gets the icon of a given path with many sizes, finally when I got exactly the class that I need, It has a problem:

This method gets icon of a given path:

public static BitmapSource GetIcon(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, 0, ref shinfo, Marshal.SizeOf(shinfo), flags);
        if (res == 0)
        {
            throw (new System.IO.FileNotFoundException());
        }

        var ico = System.Drawing.Icon.FromHandle(shinfo.hIcon); //**Here**

        var bs = BitmapFromIcon(ico);
        ico.Dispose();
        bs.Freeze();
        DestroyIcon(shinfo.hIcon);

        //   CloseHandle(shinfo.hIcon);  it always give exception
        return bs;

    }

public static extern Boolean CloseHandle(IntPtr handle);

The previous code as it is in this question works as it suppose to, however AFTER getting the icons of file paths in a directory successfully, it gives an exception on this line :
var ico = System.Drawing.Icon.FromHandle(shinfo.hIcon);

An exception of type 'System.IO.FileNotFoundException' occurred in WPF_REMOTE.exe but was not handled in user code

Additional information: Unable to find the specified file.

So Why is this happening? Update: I found out that it happened because there were a path that contains unicode characters and i need to use SHFILEINFOW instead, still can't figure how to change SHFILEINFO to SHFILEINFOW

another question about the line CloseHandle(shinfo.hIcon); always give an exception :

An exception of type 'System.Runtime.InteropServices.SEHException' occurred in WPF_REMOTE.exe but was not handled in user code

Additional information: External component has thrown an exception.

I'm wondering why it's not working! and why should I use it if the method is already working without it.

also if you have any improvement I could use in this class tell me, Thanks in Advance.

Answer 1

After editing some code I get it, you can get the icons easily from this library, in my case i needed the icon as byte[]

public class IconHelper
{
    // 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 = 256)]

        public string szDisplayName;

        // File type

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]

        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;
    }
    [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", CharSet = CharSet.Unicode)]
    public static extern int SHGetFileInfo(string pszPath, int dwFileAttributes, ref SHFILEINFO psfi, int cbFileInfo, uint uFlags);

    [DllImport("Shell32.dll", CharSet = CharSet.Unicode)]
    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; }

    }


    private static byte[] ByteFromIcon(System.Drawing.Icon ic)
    {
        var icon = System.Windows.Interop.Imaging.CreateBitmapSourceFromHIcon(ic.Handle,
                                                System.Windows.Int32Rect.Empty,
                                                System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
        icon.Freeze();
        byte[] data;
        PngBitmapEncoder encoder = new PngBitmapEncoder();
        encoder.Frames.Add(BitmapFrame.Create(icon));
        using (MemoryStream ms = new MemoryStream())
        {
            encoder.Save(ms);
            data = ms.ToArray();
        }
        return data;
    }
private static byte[] GetSmallIcon(string FileName, IconSize iconSize)
    {
        SHFILEINFO shinfo = new SHFILEINFO();
        uint flags;
        if (iconSize == IconSize.Small)
        {
            flags = SHGFI_ICON | SHGFI_SMALLICON;
        }
        else
        {
            flags = SHGFI_ICON | SHGFI_LARGEICON;
        }
        var res = SHGetFileInfo(FileName, 0, ref shinfo, Marshal.SizeOf(shinfo), flags);
        if (res == 0)
        {
            throw (new System.IO.FileNotFoundException());
        }
        var ico = (System.Drawing.Icon)System.Drawing.Icon.FromHandle(shinfo.hIcon);
        var bs = ByteFromIcon(ico);
        ico.Dispose();
        DestroyIcon(shinfo.hIcon);
        return bs;
    }

    private static byte[] GetLargeIcon(string FileName)
    {
        SHFILEINFO shinfo = new SHFILEINFO();
        uint SHGFI_SYSICONINDEX = 0x4000;
        int FILE_ATTRIBUTE_NORMAL = 0x80;
        uint flags;
        flags = SHGFI_SYSICONINDEX;
        var res = SHGetFileInfo(FileName, FILE_ATTRIBUTE_NORMAL, ref shinfo, Marshal.SizeOf(shinfo), flags);
        if (res == 0)
        {
            throw (new System.IO.FileNotFoundException());
        }
        var iconIndex = shinfo.iIcon;
        Guid iidImageList = new Guid("46EB5926-582E-4017-9FDF-E8998DAA0950");
        IImageList iml;
        int size = SHIL_EXTRALARGE;
        var hres = SHGetImageList(size, ref iidImageList, out  iml); // writes iml
        IntPtr hIcon = IntPtr.Zero;
        int ILD_TRANSPARENT = 1;
        hres = iml.GetIcon(iconIndex, ILD_TRANSPARENT, ref hIcon);
        var ico = System.Drawing.Icon.FromHandle(hIcon);
        var bs = ByteFromIcon(ico);
        ico.Dispose();
        DestroyIcon(hIcon);
        return bs;
    }

}

and you can get four different sizes for the icon