写文件 日志类

public static void WriteLine(string format)  {
            System.IO.FileStream fs = new System.IO.FileStream(("C:\\res\\log.txt"), System.IO.FileMode.Append);
            System.IO.StreamWriter streamWriter = new System.IO.StreamWriter(fs);
            streamWriter.BaseStream.Seek(0, System.IO.SeekOrigin.End);
            streamWriter.WriteLine(DateTime.Now.ToString() + " " + format);
            streamWriter.Flush();
            fs.Close();
            fs.Dispose(); 
}