StreamWriter sw = CreateAppendTxt(writePath);
                //按行写入
                sw.WriteLine(lines[i] + " " + dic[list_4[i]] + "_分块4");
                sw.Close();
//按行读取txt
            string[] lines = File.ReadAllLines(readPath, System.Text.Encoding.Default);

原文链接：https://blog.csdn.net/qq_41877039/article/details/91303620