Nlog 實現了Microsoft.Extensions.Logging.ILogger。

首先Nuget下載新增引用：NLog.Extensions.Logging

在新增NLog的配置檔案“NLog.Config” 到專案，內容如下：

<?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">

  <
 
targets>
    <target name="logfile" xsi:type="File" fileName="Log/log.txt" />
    <target name="console" xsi:type="Console" />
  </targets>

  <rules>
    <logger name="*" minlevel="Info" writeTo="logfile" />
    <logger name="*" minlevel="Info" writeTo="console" />
  </
 
rules>
</nlog>

在：Program 類（我這個是Console程式）修改：

 public static IHostBuilder CreateHostBuilder(string[] args) =>

          Host.CreateDefaultBuilder(args).ConfigureLogging(logging =>
          {
              logging.ClearProviders();
              logging.AddNLog();
              logging.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Trace);
 

          })
         .ConfigureServices((hostContext, services) =>
         {
             services.AddHostedService<DataService>();
         });

在用的地方注入Microsoft.Extensions.Logging.ILogger：

       private Microsoft.Extensions.Logging.ILogger<DataService> _logger;
        public DataService(ILogger<DataService> logger) {
            _logger = logger;
        }

        protected  void Test()
        {
         
                _logger.LogError("test.........");

最後會在Log/log.txt 記錄日誌輸出資訊。

另外可以定義為NLog.ILogger _logger;

可惜的是NLog沒有NLog.ILogger<T>這種形式！！！！

也不能直接注入NLog.ILogger，會報 'Unable to resolve service for type 'NLog.ILogger' while attempting to activate 。

可以這樣：

 private readonly Logger _logger;
 public DataService()
       {
        
            _logger = LogManager.GetCurrentClassLogger();
        }