using System;
using System.Drawing;
using System.Runtime.InteropServices;
using Microsoft.Win32;
using System.Reflection;
using System.Collections.Generic;
using System.Windows.Forms;
using System.IO;

namespace Lskj.PubArtworkPreview
{
    public static class picture
    {
        public static byte[] GetFileBytes(string fileName, bool largeIcon)
        {
            SHFILEINFO info = new SHFILEINFO(true);
            int cbFileInfo = Marshal.SizeOf(info);
            SHGFI flags;
            if (largeIcon)
                flags = SHGFI.Icon | SHGFI.LargeIcon | SHGFI.UseFileAttributes;
            else
                flags = SHGFI.Icon | SHGFI.SmallIcon | SHGFI.UseFileAttributes;

            SHGetFileInfo(fileName, 256, out info, (uint)cbFileInfo, flags);
            byte[] bytes = ImgToByte(Icon.FromHandle(info.hIcon).ToBitmap());
            info.hIcon = IntPtr.Zero; info.iIcon = 0; info.dwAttributes = 0; info.szDisplayName = ""; info.szTypeName = "";
            return bytes;
        }
        public static byte[] ImgToByte(Image img)
        {
            try
            {
                using (MemoryStream ms = new MemoryStream())
                {
                    byte[] imagedata = null;
                    img.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
                    imagedata = ms.GetBuffer();
                    return imagedata;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
                return null;
            }
        }
        [DllImport("Shell32.dll")]
        private static extern int SHGetFileInfo
          (
          string pszPath,
          uint dwFileAttributes,
          out SHFILEINFO psfi,
          uint cbfileInfo,
          SHGFI uFlags
          );

        [StructLayout(LayoutKind.Sequential)]
        private struct SHFILEINFO
        {
            public SHFILEINFO(bool b)
            {
                hIcon = IntPtr.Zero; iIcon = 0; dwAttributes = 0; szDisplayName = ""; szTypeName = "";
            }
            public IntPtr hIcon;
            public int iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.LPStr, SizeConst = 80)]
            public string szTypeName;
        }
        private enum SHGFI
        {
            SmallIcon = 0x00000001,
            LargeIcon = 0x00000000,
            Icon = 0x00000100,
            DisplayName = 0x00000200,
            Typename = 0x00000400,
            SysIconIndex = 0x00004000,
            UseFileAttributes = 0x00000010
        }
    }
}