C#文件操作

            byte[] byData = new byte[200];
            char[] charData = new Char[200];
            //Byte2Char
            Decoder d = Encoding.UTF8.GetDecoder();
            d.GetChars(byData, 0, byData.Length, charData, 0);   
             //Char2Byte
            Encoder e = Encoding.UTF8.GetEncoder();
            e.GetBytes(charData, 0, charData.Length, byData, 0, true);        

               FileStream aFile = new FileStream("Log.txt", FileMode.Open);
                StreamReader sr = new StreamReader(aFile);
                line = sr.ReadLine();
                // Read data in line by line.
                while (line != null)
                {
                    Console.WriteLine(line);
                    line = sr.ReadLine();
                }
                sr.Close();            

             FileStream aFile = new FileStream("Log.txt", FileMode.OpenOrCreate);
                StreamWriter sw = new StreamWriter(aFile);
                sw.WriteLine("now： {0} ",DateTime.Now.ToLongDateString());
                sw.Close();