创建目录

    void CrateDir(string path)  
        {
  System.IO.Directory.CreateDirectory(path);  


        }

  CrateDir(@"C:\windows\aaa");

写入文件

        void shuchu(string path,string info)
        {
            FileStream fs = new FileStream(path, FileMode.Create);


            StreamWriter sw = new StreamWriter(fs);
            sw.WriteLine(info);
            sw.Flush();
            sw.Close();
            fs.Close();


        }

 shuchu(“C:\windows\a.txt”,"123");