ASP.NET Core 添加日志NLog

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