判断文件的原始格式

很简单当笔记用

public static void FindFilename(string filePath)
        {
            try
            {
                string fileExtension = null;
                using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read))
                {
                    using (BinaryReader br = new BinaryReader(fs))
                    {
                        byte[] buffer = br.ReadBytes(2);
                        for (int i = 0; i < buffer.Length; i++)
                        {
                            fileExtension += buffer[i].ToString();
                        }
                        if (Convert.ToInt32(fileExtension)==(int)Extension.XLS)
                        {
                            Console.WriteLine("TRUE");
                        }
                        Console.Write(fileExtension);
                    }
                }

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
            }
        }

枚举：

public enum Extension
    {
        JPG = 255216,
        GIF = 7173,
        BMP = 6677,
        PNG = 13780,
        COM = 7790,
        EXE = 7790,
        DLL = 7790,
        RAR = 8297,
        ZIP = 8075,
        XML = 6063,
        HTML = 6033,
        ASPX = 239187,
        CS = 117115,
        JS = 119105,
        TXT = 210187,
        SQL = 255254,
        BAT = 64101,
        BTSEED = 10056,
        RDP = 255254,
        PSD = 5666,
        PDF = 3780,
        CHM = 7384,
        LOG = 70105,
        REG = 8269,
        HLP = 6395,
        DOC = 208207,
        XLS = 208207,
        DOCX = 208207,
        XLSX = 208207,
    }

直接判断就OK 了，我判断的是xls，不同的文件类型，读取的字节也不一样！