一、日志文件的后台应用

    1、创建一个项目=>类库(.NET Framework)

    2、引用 using System.IO

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace Common
{
    public static class FileHelper
    {
        public static void WriteLog(string log)
        {
            //获取当前目录
            var baseDir = AppDomain.CurrentDomain.BaseDirectory + "/log/";
            //文件名
            var fileName = DateTime.Now.ToString("yyyyMMdd") + ".log";
            //判断文件夹是否存在
            if(!Directory.Exists(baseDir))
            {
                //不存在，创建文件夹
                Directory.CreateDirectory(baseDir);
            }
            var newPath = baseDir + fileName;

            //using 可以自动释放资源
            using (FileStream fs=new FileStream (newPath,FileMode.Append,FileAccess.Write))
            {
                //借助 StreamWriter 来完成对文件的写操作
                using (StreamWriter sw=new StreamWriter(fs))
                {
                    sw.WriteLine(DateTime.Now + ":" + log);
                }
            }


        }
    }
}

二、在控制台中引用

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Domain;
using Service;
using Common;

namespace XiangMu_GoMai3.Controllers
{
    public class LoginController : Controller
    {
        LoginBll loginBll = new LoginBll();
        //登录视图
        public ActionResult Index()
        {
            return View();
        }
        //登录功能
        [HttpPost]
        public ActionResult  Login(string uname, string upass)
        {
            var result = loginBll.Login(uname, upass);
            if(result!=null)
            {
                Session["UserName"] = result.UName;

                //记录日志
                FileHelper.WriteLog("用户名:" + uname + "登录成功");

                return Json(1, JsonRequestBehavior.DenyGet);
            }
            else
            {
                //记录日志
                FileHelper.WriteLog("用户名:" + uname + "登录失败");
                return Json(0, JsonRequestBehavior.DenyGet);
            }
        }
    }
}