C#下获取文件编码的方式。缺陷是：只能判别Unicode，Unicode-Big Endian和UTF-8格式（通过流方式读取文件的BOM：ByteOrderMarks）；如果不是这三种编码格式，就判别为系统默认编码格式。请大家指正，提出好的解决方案：能判别Windows/.Net支持的所有编码格式！很期待..

　　注：编码对应的BOM如下

           Unicode {0xFF, 0xFE}
           Unicode-Big Endian {0xFE, 0xFF}
           UTF-8 {0xEF, 0xBB, 0xBF}

public static Encoding GetEncoding(FileStream stream, Encoding defaultEncoding) { Encoding targetEncoding = defaultEncoding; #region Via BOM: ByteOrderMarks if (stream != null && stream.Length >= 2) { //Store the first 4 Bytes of file stream byte byte1 = 0; byte byte2 = 0; byte byte3 = 0; byte byte4 = 0; //Store the current position of seek long origPos = stream.Seek(0, SeekOrigin.Begin); stream.Seek(0, SeekOrigin.Begin); int nByte = stream.ReadByte(); byte1 = Convert.ToByte(nByte); byte2 = Convert.ToByte(stream.ReadByte()); if (stream.Length >= 3) { byte3 = Convert.ToByte(stream.ReadByte()); } if (stream.Length >= 4) { byte4 = Convert.ToByte(stream.ReadByte()); } //Identify the encoding according to the first 4 Bytes of the file stream //Unicode {0xFF, 0xFE} //Unicode-Big Endian {0xFE, 0xFF} //UTF-8 {0xEF, 0xBB, 0xBF} if (byte1 == 0xFE && byte2 == 0xFF)//Unicode-Big Endian { targetEncoding = Encoding.BigEndianUnicode; } if (byte1 == 0xFF && byte2 == 0xFE && byte3 != 0xFF)//Unicode { targetEncoding = Encoding.Unicode; } if (byte1 == 0xEF && byte2 == 0xBB && byte3 == 0xBF)//UTF-8 { targetEncoding = Encoding.UTF8; } //Restore Seek position stream.Seek(origPos, SeekOrigin.Begin); } #endregion return targetEncoding; }