1.在Nuget上搜索 NLog.Extensions.Logging 安装最新版

2.添加日志配置文件，在项目指定目录下添加配置文件nlog.config，内容添加如下：

<?xml version="1.0" encoding="utf-8" ?><nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      autoReload="true"      internalLogLevel="Warn"      internalLogFile="c:\temp\internal-nlog.txt">  <!-- define various log targets -->  <targets>    <!-- write logs to file -->    <target xsi:type="File" name="allfile" fileName="c:\temp\nlog-all-${shortdate}.log"                 layout="${longdate}|${event-properties:item=EventId.Id}|${logger}|${uppercase:${level}}|${message} ${exception}" />       <target xsi:type="File" name="ownFile-web" fileName="c:\temp\nlog-own-${shortdate}.log"             layout="${longdate}|${event-properties:item=EventId.Id}|${logger}|${uppercase:${level}}|  ${message} ${exception}" />    <target xsi:type="Null" name="blackhole" />  </targets>  <rules>    <!--All logs, including from Microsoft-->    <logger name="*" minlevel="Trace" writeTo="allfile" />    <!--Skip Microsoft logs and so log only own logs-->    <logger name="Microsoft.*" minlevel="Trace" writeTo="blackhole" final="true" />    <logger name="*" minlevel="Trace" writeTo="ownFile-web" />  </rules></nlog>

3.将nlog.config添加到project.json配置文件中(若配置文件在指定config目录下，可以添加config/*.config)

  "publishOptions": {        "include": [            "wwwroot",            "Views",            "appsettings.json",            "web.config",            "nlog.config"        ]    },

4.在startup.cs文件Configure中添加

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
loggerFactory.AddNLog();
env.ConfigureNLog("nlog.config");
…………

5.记录日志方法

(1) public class HomeController : Controller    {        private static Logger Logger = LogManager.GetCurrentClassLogger();        public IActionResult Index()        {            Logger.Info("Index page says hello");            return View();        }
    …………


(2) public abstract class BaseController<T> : Controller
    {
     protected ILogger<T> Logger { get; set; }

    public BaseController(ILogger<T> logger, IOptions<ApplicationSiteConfig> appConfig)
   {
      this.Logger = logger;
   }
…………

参考：https://github.com/NLog/NLog.Extensions.Logging 

ASP.NET Core 添加日志NLog