获取文件图标

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.IO;
public class FileIcon{
    /// <summary>
    ///  Get default icon from file
    /// </summary>
    /// <param name="fileName">File name
    /// </param>
    /// <param name="largeIcon">Large icon or not</param>
    /// <returns>default icon</returns>
    public static Icon GetFileIcon(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);
        return Icon.FromHandle(info.hIcon);
    }


    [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 s{
        SmallIcon = 0x00000001,
        LargeIcon = 0x00000000,
        Icon = 0x00000100,
        DisplayName = 0x00000200,
        Typename = 0x00000400,
        SysIconIndex = 0x00004000,
        UseFileAttributes = 0x00000010
    }
}