一个判断文本文件编码的类.txt

 public class EncodingType
    {
        public static System.Text.Encoding GetType(string FILE_NAME)
        {
            FileStream fs = new FileStream(FILE_NAME, FileMode.Open, FileAccess.Read);
            System.Text.Encoding r= GetType(fs);
            fs.Close();
            return r;
        }
        public static System.Text.Encoding GetType(FileStream fs)
        {
            /*byte[] Unicode=new byte[]{0xFF,0xFE};
            byte[] UnicodeBIG=new byte[]{0xFE,0xFF};
            byte[] UTF8=new byte[]{0xEF,0xBB,0xBF};*/

            BinaryReader r = new BinaryReader(fs,System.Text.Encoding.Default);
            byte[] ss=r.ReadBytes(3);
            r.Close();
            //编码类型 Coding=编码类型.ASCII;
            if(ss[0]>=0xEF)
            {
                if(ss[0]==0xEF && ss[1]==0xBB && ss[2]==0xBF)
                {
                    return System.Text.Encoding.UTF8;
                }
                else if(ss[0]==0xFE && ss[1]==0xFF)
                {
                    return System.Text.Encoding.BigEndianUnicode;
                }
                else if(ss[0]==0xFF && ss[1]==0xFE)
                {
                    return System.Text.Encoding.Unicode;
                }
                else
                {
                    return System.Text.Encoding.Default;
                }
            }
            else
            {
                return System.Text.Encoding.Default;
            }
        }
    }