using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System;namespace ConsoleApp0
{class Program{static void Main(string[] args){Console.WriteLine("Hello World! from console");ILogger logger;IFooService fooService;using (var serviceProvider = new ServiceCollection().AddSingleton<IFooService, FooService>().AddLogging(cfg =>{cfg.AddConsole();}).BuildServiceProvider()){logger = serviceProvider.GetService<ILogger<Program>>();fooService = serviceProvider.GetService<IFooService>();}logger.LogInformation("logger information");logger.LogWarning("logger warning");fooService.DoWork();}}public interface IFooService{void DoWork();}public class FooService : IFooService{private readonly ILogger logger;public FooService(ILogger<FooService> logger){this.logger = logger;}public void DoWork(){logger.LogInformation("Doing work.");logger.LogWarning("Something warning");logger.LogCritical("Something critical");}}
}

这是执行效果：

.AddLogging(cfg => { cfg.AddConsole(cfg=> cfg.DisableColors=true); })
.BuildServiceProvider())

文件中配置

var configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json", false, true).Build();ILogger logger;
IFooService fooService;using (var serviceProvider = new ServiceCollection()// thanks to // https://thecodebuzz.com/logging-in-net-core-console-application/.AddSingleton<IFooService, FooService>().AddLogging(cfg => {cfg.AddConfiguration(configuration.GetSection("Logging"));cfg.AddConsole(); }).BuildServiceProvider()){logger = serviceProvider.GetService<ILogger<Program>>();//logger = serviceProvider.GetService<ILoggerFactory>().CreateLogger<Program>(); // Factory first. This works too.fooService = serviceProvider.GetService<IFooService>();}

而appsettings.json内容如下：

{"Logging": {"Console": {"disableColors": false},"LogLevel": {"Default": "Information","Microsoft": "Information","ConsoleApp1.FooService": "Warning","ConsoleApp1.Program": "Debug"}}
}

提示

using (var listener = new TextWriterTraceListener("c:\\temp\\mylog.txt"))
using (var consoleListener = new ConsoleTraceListener())
{Trace.Listeners.Add(listener);Trace.Listeners.Add(consoleListener);

因此，您必须实例化跟踪侦听器，并在应用程序startup代码中进行初始化Trace和TraceSources对象。不错，但是事情还在继续，有越来越多的第三方组件可以与ILogger<T>接口进行跟踪和日志记录。考虑到各种因素和权衡取舍，最好在TraceSource和ILogger<T>之间架起一座桥梁，因此使用Trace和TraceSource的遗留组件可以向ILogger<T>发送跟踪消息。

public class LoggerTraceListener : TraceListener
{private readonly ILogger logger;public LoggerTraceListener(ILogger logger){this.logger = logger;}public override void Write(string message){logger.LogInformation(message);}public override void WriteLine(string message){logger.LogInformation(message);}public override void WriteLine(string message, string category){logger.LogInformation(category + ": " + message);}public override void TraceEvent(TraceEventCache eventCache, string source, TraceEventType eventType, int id){switch (eventType){case TraceEventType.Critical:logger.LogCritical(id, source);break;case TraceEventType.Error:logger.LogError(id, source);break;case TraceEventType.Warning:logger.LogWarning(id, source);break;case TraceEventType.Information:logger.LogInformation(id, source);break;case TraceEventType.Verbose:logger.LogTrace(id, source);break;case TraceEventType.Start:logger.LogInformation(id, "Start: " + source);break;case TraceEventType.Stop:logger.LogInformation(id, "Stop: " + source);break;case TraceEventType.Suspend:logger.LogInformation(id, "Suspend: " + source);break;case TraceEventType.Resume:logger.LogInformation(id, "Resume: " + source);break;case TraceEventType.Transfer:logger.LogInformation(id, "Transfer: " + source);break;default:throw new InvalidOperationException("Impossible");}}

应用程序启动(startup)：

ILogger logger;using (var serviceProvider = new ServiceCollection().AddLogging(cfg =>{cfg.AddConfiguration(configuration.GetSection("Logging"));cfg.AddConsole();}).BuildServiceProvider())
{logger = serviceProvider.GetService<ILogger<Program>>();
}logger.LogInformation("logger information");
logger.LogWarning("logger warning");using (var listener = new LoggerTraceListener(logger))
{System.Diagnostics.Trace.Listeners.Add(listener);TraceSources.Instance.InitLoggerTraceListener(listener);TraceLover.DoSomething();TraceSourceLover.DoSomething();
}

现在，Trace和TraceSource的日志介质是由哪些日志提供程序附加到ILogger决定的。

var configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json", false, true).Build();Serilog.Log.Logger = new Serilog.LoggerConfiguration().Enrich.FromLogContext()//.WriteTo.Console() I prefer plugging through the config file.ReadFrom.Configuration(configuration).CreateLogger();Microsoft.Extensions.Logging.ILogger logger;
IFooService fooService;var services = new ServiceCollection();
services.AddLogging(configure => configure.AddSerilog());using (var serviceProvider = services.AddSingleton<IFooService, FooService>().BuildServiceProvider())
{logger = serviceProvider.GetService<ILogger<Program>>();fooService = serviceProvider.GetService<IFooService>();
}try
{Log.Information("Starting up");logger.LogInformation("logger information");logger.LogWarning("logger warning");fooService.DoWork();using (var listener = new LoggerTraceListener(logger)){System.Diagnostics.Trace.Listeners.Add(listener);TraceSources.Instance.InitLoggerTraceListener(listener);TraceLover.DoSomething();TraceSourceLover.DoSomething();}
}
catch (Exception ex)
{Log.Fatal(ex, "Application start-up failed");
}
finally
{Log.CloseAndFlush();
}

而appsettings.json内容如下：

{"TraceSource": {"WebApi": {"SourceLevels": "Information"},"HouseKeeping": { "SourceLevels": "Warning" },"DbAudit": {"SourceLevels": "Warning"}},"Serilog": {"MinimumLevel": {"Default": "Debug","Override": {"Microsoft": "Information","System": "Warning","ConsoleApp1.FooService": "Warning","ConsoleApp1.Program": "Information"}},"WriteTo": [{"Name": "Console"},{"Name": "File","Args": {"path": "%PROGRAMDATA%/my/logs/CloudPosApi_Test.log","outputTemplate": "{Timestamp:MM-dd HH:mm:ss.fff zzz} [{Level}] {ThreadId} {Message}{NewLine}{Exception}","rollingInterval": "Day"}}]}
}

兴趣点