在不使用nlog.config文件的ASP.NET核心2.0中配置NLog

using Microsoft.Extensions.Logging;
using NLog.Extensions.Logging;

public class Startup
{
    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
        // 添加NLog作为日志提供程序
        loggerFactory.AddNLog();

        // 配置NLog
        env.ConfigureNLog("nlog.config");

        // 其他配置代码...
    }
}

<?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">

  <targets>
    <target xsi:type="File" name="file" fileName="log.txt" />
  </targets>

  <rules>
    <logger name="*" minlevel="Trace" writeTo="file" />
  </rules>
</nlog>

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

public class HomeController : Controller
{
    private readonly ILogger<HomeController> _logger;

    public HomeController(ILogger<HomeController> logger)
    {
        _logger = logger;
    }

    public IActionResult Index()
    {
        _logger.LogInformation("Hello, NLog!");

        return View();
    }
}