文件读写

FileStream fs = new FileStream(@c:\temp\test.txt , FileMode.OpenOrCreate, FileAccess.Write);
        StreamWriter sw = new StreamWriter(fs);
        // Write to the file using StreamWriter class
        sw.BaseStream.Seek(0, SeekOrigin.End);
        sw.WriteLine( First Line );
        sw.WriteLine( Second Line);
        sw.Flush();