C#取得文件或扩展名的ICO

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

namespace Fine.RefAPI
{
    public class FileHelper
    {
        #region 取得檔案中包含的所有圖標
        [DllImport("shell32.dll", CharSet = CharSet.Auto)]
        private static extern int ExtractIconEx(string path, int i, IntPtr[] big, IntPtr[] small, uint op);

        /// <summary>
        /// Get file contain's all icons
        /// </summary>
        /// <param name="FilePath">file path</param>
        /// <returns>icon</returns>
        static public Icon[] GetFileIcons(string FilePath)
        {
            try
            {
                int IconsNum = ExtractIconEx(FilePath, -1, null, null, 0); //get file icons count
                if (IconsNum <= 0)
                    return null;
                IntPtr[] LargeIcons = new IntPtr[IconsNum];
                IntPtr[] SmallIcons = new IntPtr[IconsNum];