FileIconUtility

using System.Runtime.InteropServices;

namespace System.Drawing
{
    /// <summary>
    /// Utility to get the default icon from files
    /// </summary>
    public class FileIconUtility
    {
        const uint SHGFI_SYSICONINDEX = 0x4000;
        const uint SHGFI_ICON = 0x100;
        const uint SHGFI_LARGEICON = 0x0;
        const uint SHGFI_SMALLICON = 0x1;

        [StructLayout(LayoutKind.Sequential)]
        struct SHFILEINFO
        {
            public IntPtr hIcon;
            public int iIcon;
            public int dwAttributes;
            public string szDisplayName;
            public string szTypeName;
        }

        [DllImport("Shell32.dll")]
        static extern int SHGetFileInfo(string path,uint fileAttributes,out SHFILEINFO psfi,uint fileInfo,uint flags);

        [DllImport("kernel32.dll",SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool CloseHandle(IntPtr hObject);


        public static Icon GetIcon(string path)
        {
            return GetIcon(path,IconSize.Small);
        }

        public static Icon GetIcon(string path,IconSize iconSize)
        {
            SHFILEINFO info = new SHFILEINFO();

            uint size = iconSize == IconSize.Large ? SHGFI_LARGEICON : SHGFI_SMALLICON;

            uint flags = SHGFI_SYSICONINDEX | size | SHGFI_ICON;
            int hTcdf = SHGetFileInfo(path,0,out info,(uint)Marshal.SizeOf(typeof(SHFILEINFO)),flags);

            IntPtr handleIcon = info.hIcon;
            try
            {
                Icon ico = Icon.FromHandle(handleIcon);
                return ico;
            }
            finally
            {
                if(handleIcon != IntPtr.Zero)
                    CloseHandle(handleIcon);
            }
        }
    }

    public enum IconSize
    {
        Large,
        Small
    }

}