TxT读取写入

/// 读
  public void inint()
        {
            FileStream fs = new FileStream("D:/123.txt",FileMode.Open,FileAccess.Read );
            StreamReader sr = new StreamReader(fs);
            sr.BaseStream.Seek(0, SeekOrigin.Begin);

            string str = sr.ReadToEnd();
            if (str!="")
            {
                Console.WriteLine("{0}", str);
                str = sr.ReadLine();

            }
            sr.Close();
            fs.Close();
        }

///写入
            using (StreamWriter sw=File.AppendText("D:/123.txt"))
            {
                sw.Write("我爱你中国");
                sw.Dispose();
            }