C# ILogger未将跟踪和调试消息写入目标

我正在ASP.NET Core 3应用程序中设置一些日志记录，使用ILogger（Microsoft.Extensions.logging）和NLog来支持对文本文件的写入

问题是，ILogger不写入跟踪和调试级别的消息。可以是文本文件，也可以是Visual Studio输出窗口。使用NLog.Logger可以处理所有级别。这个问题也存在于默认的ASP.NET Core 3 Web API应用程序中，该应用程序的NLog是根据其官方教程设置的。以下是我的相关代码

Program.cs

public static void Main(string[] args)
{
    var logger = NLog.Web.NLogBuilder.ConfigureNLog("nlog.config").GetCurrentClassLogger();
    try
    {
        logger.Trace("NLog Trace from Main()");
        logger.Debug("NLog Debug from Main()");
        logger.Info("NLog Info from Main()");
        logger.Warn("NLog Warn from Main()");
        logger.Error("NLog Error from Main()");
        logger.Fatal("NLog Fatal from Main()");
        CreateHostBuilder(args).Build().Run();
    }
    catch (Exception exception)
    {
        //NLog: catch setup errors
        logger.Error(exception, "Stopped program because of exception");
        throw;
    }
    finally
    {
        // Ensure to flush and stop internal timers/threads before application-exit (Avoid segmentation fault on Linux)
        NLog.LogManager.Shutdown();
    }
}

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        })
        .ConfigureLogging(options =>
        {
            options.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace);
        }).UseNLog();

private readonly ILogger<WeatherForecastController> _logger;

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

[HttpGet]
public IEnumerable<WeatherForecast> Get()
{
    _logger.LogTrace("ILogger LogTrace from WeatherForecastController.");
    _logger.LogDebug("ILogger LogDebug from WeatherForecastController.");
    _logger.LogInformation("ILogger LogInformation from WeatherForecastController.");
    _logger.LogWarning("ILogger LogWarning from WeatherForecastController.");
    _logger.LogError("ILogger LogError from WeatherForecastController.");
    _logger.LogCritical("ILogger LogCritical from WeatherForecastController.");
    var rng = new Random();
    return Enumerable.Range(1, 5).Select(index => new WeatherForecast
    {
        Date = DateTime.Now.AddDays(index),
        TemperatureC = rng.Next(-20, 55),
        Summary = Summaries[rng.Next(Summaries.Length)]
    })
    .ToArray();
}

WeatherForecastController.cs

public static void Main(string[] args)
{
    var logger = NLog.Web.NLogBuilder.ConfigureNLog("nlog.config").GetCurrentClassLogger();
    try
    {
        logger.Trace("NLog Trace from Main()");
        logger.Debug("NLog Debug from Main()");
        logger.Info("NLog Info from Main()");
        logger.Warn("NLog Warn from Main()");
        logger.Error("NLog Error from Main()");
        logger.Fatal("NLog Fatal from Main()");
        CreateHostBuilder(args).Build().Run();
    }
    catch (Exception exception)
    {
        //NLog: catch setup errors
        logger.Error(exception, "Stopped program because of exception");
        throw;
    }
    finally
    {
        // Ensure to flush and stop internal timers/threads before application-exit (Avoid segmentation fault on Linux)
        NLog.LogManager.Shutdown();
    }
}

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        })
        .ConfigureLogging(options =>
        {
            options.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace);
        }).UseNLog();

private readonly ILogger<WeatherForecastController> _logger;

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

[HttpGet]
public IEnumerable<WeatherForecast> Get()
{
    _logger.LogTrace("ILogger LogTrace from WeatherForecastController.");
    _logger.LogDebug("ILogger LogDebug from WeatherForecastController.");
    _logger.LogInformation("ILogger LogInformation from WeatherForecastController.");
    _logger.LogWarning("ILogger LogWarning from WeatherForecastController.");
    _logger.LogError("ILogger LogError from WeatherForecastController.");
    _logger.LogCritical("ILogger LogCritical from WeatherForecastController.");
    var rng = new Random();
    return Enumerable.Range(1, 5).Select(index => new WeatherForecast
    {
        Date = DateTime.Now.AddDays(index),
        TemperatureC = rng.Next(-20, 55),
        Summary = Summaries[rng.Next(Summaries.Length)]
    })
    .ToArray();
}

现在有人能告诉我为什么ILogger不写跟踪和调试消息吗？我已经在谷歌上搜索了几个小时，就我所知，一切都应该正确设置（？）

---

谢谢大家!

正如rolf所说，如果您只是使用Visual studio IIS express调试asp.net core应用程序，那么应该使用appsettings.development.json而不是appsettings.json，因为ASPNETCORE_环境变量已更改为

development

您可以在launchSettings.json中找到以下设置：

  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "launchUrl": "weatherforecast",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "CoreWebAPIIssue": {
      "commandName": "Project",
      "launchBrowser": true,
      "launchUrl": "weatherforecast",
      "applicationUrl": "https://localhost:5001;http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }

您应该修改appsettings.development.json，如下所示：

{
  "Logging": {
    "LogLevel": {
      "Default": "Trace",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  }
}

结果是：

---

您的

appsettings.json

看起来不错。您是否还检查了是否有任何特定于环境的文件，如

appsettings.development.json

？也见我的上帝。真的那么简单吗？我完全忽略了这一点。非常感谢@RolfKristensen。现在一切正常。你的评论应该是真正的答案。@RolfKristensen是对的。现在可以了。感谢你详细阐述他的评论。

{
  "Logging": {
    "LogLevel": {
      "Default": "Trace",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  }
}