สร้างโปรเจ็กส์แบบ ASP.NET Core Web App (Model-View-Controller)

1. ทดสอบ logger

ที่ไฟล์ Controllers/HomeController.cs เพิ่มโค๊ด _logger.* ไว้ดูผลการ log

using Microsoft.AspNetCore.Mvc;
using System.Diagnostics;
using WebMvc6.Models;

namespace WebMvc6.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;

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

        public IActionResult Index()
        {
            _logger.LogInformation("This is an INFORMATION message.");
            _logger.LogWarning("This is a WARNING message.");
            _logger.LogError("This is an ERROR message.");

            return View();
        }

        public IActionResult Privacy()
        {
            return View();
        }

        [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }
    }
}

เปิดหน้าต่าง Output โดยไปที่เมนู View | Output

ทดลองเรียกไปที่หน้า Home เช่น https://localhost:7138/ แล้วดูที่หน้าต่าง Output

WebMvc6.Controllers.HomeController: Information: This is an INFORMATION message.
WebMvc6.Controllers.HomeController: Warning: This is a WARNING message.
WebMvc6.Controllers.HomeController: Error: This is an ERROR message.

2. ใช้ log4net

ติดตั้ง Package log4net และ Microsoft.Extensions.Logging.Log4Net.AspNetCore

• NuGet Gallery | log4net 2.0.15
• NuGet Gallery | Microsoft.Extensions.Logging.Log4Net.AspNetCore 6.1.0

PM> NuGet\Install-Package log4net -Version 2.0.15
PM> NuGet\Install-Package Microsoft.Extensions.Logging.Log4Net.AspNetCore -Version 6.1.0

สร้างไฟล์ log4net.config

<?xml version="1.0" encoding="utf-8" ?>
<log4net>
  <appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock"/>
    <file value="log/" />
    <datePattern value="yyMMdd'Jack.log'" />
    <staticLogFileName value="false"/>
    <appendToFile value="true"/>
    <rollingStyle value="Date"/>
    <maxSizeRollBackups value="100"/>
    <maximumFileSize value="15MB"/>
    <encoding value="UTF-8"/>
    <layout type="log4net.Layout.PatternLayout">
      <param name="ConversionPattern" value="%-5p%d{ HH:mm:ss} li:%line - [%method] %m  %n" />
    </layout>
  </appender>
  <root>
    <level value="ALL"/>
    <appender-ref ref="RollingLogFileAppender"/>
  </root>
</log4net>

แก้ไขไฟล์ Program.cs

var builder = WebApplication.CreateBuilder(args);

ILoggerFactory _loggerFactory = (ILoggerFactory)new LoggerFactory();
_loggerFactory.AddLog4Net();
builder.Services.AddSingleton(_loggerFactory);

// Add services to the container.
builder.Services.AddControllersWithViews();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

ทดลองเรียกหน้า Home อีกครั้งจะได้ไฟล์ .log