如何在 ASP.NET Webforms 中使用 Autofac 注入 NLog

Question

我有一个 ASP.NET Webforms 项目，我最近将其转换为通过 Autofac 使用依赖注入。一切进展顺利，直到我尝试注入我的 NLog 实例。我不知道如何使用属性注入的 Logger 对象执行静态 GetCurrentClassLogger() 方法调用的等效方法。

这是说明问题的示例代码：

Global.asax.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

using Autofac;
using Autofac.Integration.Web;

public class Global : HttpApplication, IContainerProviderAccessor
{
  private static IContainerProvider containerProvider;

  public IContainerProvider ContainerProvider
  {
    get { return containerProvider; }
  }

  void Application_Start(object sender, EventArgs e)
  {
    var builder = new ContainerBuilder();
    Bootstrapper.RegisterInstances(builder);
    containerProvider = new ContainerProvider(builder.Build());
  }
}

Bootstrapper.cs

using Autofac;

public static class Bootstrapper
{
  public static void RegisterInstances(ContainerBuilder builder)
  {
    builder.RegisterType<Logger>().As<ILogger>().InstancePerRequest();
    builder.RegisterType<MyTestModule>().As<IMyTestModule>().InstancePerRequest();
  }
}

MyTestModule.cs

using System;

public class MyTestModule : IMyTestModule
{
   // was previously: protected static readonly ILogger Logger = LogManager.GetCurrentClassLogger();

  private ILogger _logger;

  public MyTestModule(ILogger logger)
  {
    _logger = logger;
  }

  public void DoSomethingBad()
  {
    try
    {
        int z = 5 / 0;
    }
    catch (Exception ex)
    {
        _logger.Error("Error!", ex);
    }
  }
}

public interface IMyTestModule
{
  void DoSomethingBad();
}

PageBase.cs

public abstract class PageBase : Page
{
  // was previously: protected static readonly ILogger Logger = LogManager.GetCurrentClassLogger();

  public ILogger Logger { get; set; }

  public IMyTestModule MyTestModuleInstance { get; set; }
}

Default.aspx

<%@ Page Title="Home" Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<html>
  <head></head>
  <body></body>
</html>

Default.aspx.cs

using System;

public partial class _Default : PageBase
{
  protected void Page_Load(object sender, EventArgs e)
  {
    MyTestModuleInstance.DoSomethingBad();
  }
}

可以看到在PageBase.cs和MyTestModule.cs我已经注释掉了之前静态调用创建NLog 实例：

protected static readonly ILogger Logger = LogManager.GetCurrentClassLogger();

它们现在简单地替换为注入的 Autofac 依赖项属性，如下所示：

public ILogger Logger { get; set; }

这非常有效，以至于 Logger 对象被初始化为记录器的一个实例。

我如何执行相当于 LogManager.GetCurrentClassLogger() 的操作？

我需要对 NLog 模块做些什么才能实现这个目标吗？如果有的话，我找不到任何具体的例子。任何帮助将不胜感激！

Answer 1

覆盖模块的 AttachTocomponentRegistaration：

public class AutofacLogInjectionModule : Module
{
    protected override void AttachToComponentRegistration(IComponentRegistry registry, IComponentRegistration registration)
    {
        registration.Preparing += OnComponentPreparing;
    }

    static void OnComponentPreparing(object sender, PreparingEventArgs e)
    {
        e.Parameters = e.Parameters.Union(new[]
    {
        new ResolvedParameter((p, i) => p.ParameterType == typeof(ILogger), (p, i) => LogManager.GetCurrentClassLogger())
    });
    }

}

并在您的 bootstrap 中注册此模块：

builder.RegisterModule(new AutofacLogInjectionModule());

如何在 ASP.NET Webforms 中使用 Autofac 注入 NLog

How to inject NLog using Autofac in ASP.NET Webforms

c#

asp.net

webforms

nlog

autofac