ShellIcon.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Drawing;
using System.IO;

namespace Herring
{
    /// <summary>
    /// Summary description for ShellIcon.  Get a small or large Icon with an easy C# function call
    /// that returns a 32x32 or 16x16 System.Drawing.Icon depending on which function you call
    /// either GetSmallIcon(string fileName) or GetLargeIcon(string fileName)
    /// </summary>
    public static class ShellIcon
    {
        [StructLayout(LayoutKind.Sequential)]
        public struct SHFILEINFO
        {
            public IntPtr hIcon;
            public IntPtr iIcon;
            public uint dwAttributes;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string szDisplayName;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
            public string szTypeName;
        };

        class Win32
        {
            public const uint SHGFI_ICON = 0x100;
            public const uint SHGFI_LARGEICON = 0x0; // 'Large icon
            public const uint SHGFI_SMALLICON = 0x1; // 'Small icon

            [DllImport("shell32.dll")]
            public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbSizeFileInfo, uint uFlags);

            [DllImport("User32.dll")]
            public static extern int DestroyIcon(IntPtr hIcon);

        }

        static ShellIcon()
        {

        }

        public static Icon GetSmallIcon(string fileName)
        {
            return GetIcon(fileName, Win32.SHGFI_SMALLICON);
        }

        public static Icon GetLargeIcon(string fileName)
        {
            Icon result = GetIcon(fileName, Win32.SHGFI_LARGEICON);
            return result;
        }

        private static Icon GetIcon(string fileName, uint flags)
        {
            if (File.Exists(fileName) == false)
            {
                return null;
            }
            SHFILEINFO shinfo = new SHFILEINFO();
            IntPtr hImgSmall = Win32.SHGetFileInfo(fileName, 0, ref shinfo, (uint)Marshal.SizeOf(shinfo), Win32.SHGFI_ICON | flags);
            if (shinfo.hIcon == IntPtr.Zero)
            {
                return null;
            }
            else
            {
                Icon icon = (Icon)System.Drawing.Icon.FromHandle(shinfo.hIcon).Clone();
                Win32.DestroyIcon(shinfo.hIcon);
                return icon;
            }
        }

        public static Bitmap ConvertIconToBitmap(Icon icon)
        {
             Bitmap bmp = new Bitmap(icon.Size.Width, icon.Size.Height);
             using (Graphics g = Graphics.FromImage(bmp))
                 g.DrawIcon(icon, 0, 0);
             return bmp;
        }
        

    }
}