vs升级到2015后修改文件编码解决乱码问题

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Runtime.Remoting.Messaging;
using System.Text;
using System.Threading.Tasks;

namespace FileEncode
{
    class Program
    {
        static void Main(string[] args)
        {
            if (File.Exists(args[0]))
            {
                ProcessFile(args[0]);
            }

            if (Directory.Exists(args[0]))
            {
                var dir = args[0];

                ProcessDir(dir);
                
            }
        }


        private static void ProcessFile(string fileName)
        {
            var fi = new FileInfo(fileName);
            var sb = new StringBuilder();
            using (var fs = fi.OpenRead())
            {
                using (var br = new BinaryReader(fs))
                {
                    var firstTwobytes = br.ReadBytes(2);
                    foreach (var firstTwobyte in firstTwobytes)
                    {
                        sb.Append(firstTwobyte.ToString("X"));
                    }
                }
            }

            var encoding = sb.ToString();

            if (encoding != "EFBB")
            {
                Console.WriteLine($"{fileName} {encoding}");

                File.WriteAllText(fileName,File.ReadAllText(fileName,Encoding.Default),Encoding.UTF8);
            }


        }


        private static void ProcessDir(string dir)
        {
            var files = Directory.GetFiles(dir);

            var fileInfos = (from file in files let fi = new FileInfo(file) where fi.Extension == ".js" select file).ToList();

            foreach (var fileInfo in fileInfos)
            {
                ProcessFile(fileInfo);
            }

            var dirs = Directory.GetDirectories(dir);

            foreach (var s in dirs)
            {
                ProcessDir(s);
            }
        }
    }
}