C#txt文件创建并写入信息

        public static void LogWrite(string str)
        {
          //项目根目录
          string path = HttpContext.Current.Server.MapPath("~") + "ilogs.txt";

            if (!File.Exists(path))
            {
                FileStream fs = new FileStream(path, FileMode.Create,FileAccess.ReadWrite);

                StreamWriter sw = new StreamWriter(fs);
                sw.Write(str);
                sw.Flush();
                sw.Close();
            }
            else
            {
                FileStream fs = new FileStream(path, FileMode.Append);
                //文本写入
                StreamWriter sw = new StreamWriter(fs);
                sw.Write(str);
                sw.Flush();
                sw.Close();
            }
        }