Castle Windsor won't inject Logger in a proper

问题:

I try to inject log4net in a ILogger property of my service class but the property is always NULL!

I've seen this topic but it doesn't help me!

How can I get Castle Windsor to automatically inject a property?

this is Program.cs

 CastleContainer.Instance
        .Install(
          new RepositoriesInstaller(),
          new PersistenceInstaller(),
          new LoggerInstaller(),
          new FormInstaller(),
          new ServiceInstaller()

          );

        FrmStart form1 = CastleContainer.Resolve<FrmStart>(new {Id="666" });

I use log4net.config external file and this is my installer:

public class LoggerInstaller : IWindsorInstaller
{
    #region IWindsorInstaller Members

    public void Install(IWindsorContainer container, IConfigurationStore store)
    {
         container.AddFacility("logging", new LoggingFacility(LoggerImplementation.Log4net, "log4net.config"));
    }

    #endregion
}

This is the class contains the property I want Windsor to inject:

public partial class FrmStart : Form
{
    private EventService EventService;

    private ILogger logger = NullLogger.Instance;
    public ILogger Logger
    {
        get { return logger; }
        set { logger = value; }
    }

    public FrmStart(EventService eventService, string Id)
        : this()
    {

        Logger.Debug("xxx");

        this.EventService = eventService;
        this.id = Id;
    }

Note that "eventService" and "Id" in the constructor are correctly injected! If I try to inject the Logger in the constructor it works and I've the Logger object: {log4net.Repository.Hierarchy.DefaultLoggerFactory+LoggerImpl}! :-(

I've tried to create a public property for EventService and Windsor can inject it properly! So I think the problem is related only to the ILogger interface.

I prepared a simple full-code example here:

using Castle.Core.Logging;
using Castle.Facilities.Logging;
using Castle.MicroKernel.Registration;
using Castle.MicroKernel.SubSystems.Configuration;
using Castle.Windsor;

namespace IocTest
{


public class LoggerInstaller : IWindsorInstaller
{
    public void Install(IWindsorContainer container, IConfigurationStore store)
    {
         container.AddFacility("logger", new LoggingFacility(LoggerImplementation.Log4net, "log4net.config"));
    }
}
public class LogicInstaller : IWindsorInstaller
{
     public void Install(IWindsorContainer container, IConfigurationStore store)
    {
        container.Register(AllTypes.FromThisAssembly()
                            .Pick()
                            .If(t => t.Name.StartsWith("Logic"))
                            .Configure((c => c.LifeStyle.Transient)));
    }
}

class Program
{
    static void Main(string[] args)
    {
        IWindsorContainer container = new WindsorContainer();

        container.Install(
        new LoggerInstaller(),
          new LogicInstaller()
          );


        LogicClass1 logic1 = container.Resolve<LogicClass1>();
        LogicClass2 logic2 = container.Resolve<LogicClass2>();
    }
}

public class LogicClass1
{
    private ILogger logger = NullLogger.Instance;
    public ILogger Logger
    {
        get { return logger; }
        set { logger = value; }
    }

    public LogicClass1()
    {
        logger.Debug("Here logger is NullLogger!");
    }
}

public class LogicClass2
{
    public LogicClass2(ILogger logger)
    {
        logger.Debug("Here logger is properly injected!");
    }
}
}

What's wrong?

回答1:

A problem is where you are checking it:

 public ILogger Logger
    {
        get { return logger; }
        set { logger = value; }
    }

    public LogicClass1()
    {
        logger.Debug("Here logger is NullLogger!");
    }

The property injection will not happen until after the constructor is run, so checking the property value in the constructor will never show the value you are expecting

回答2:

I was having the same problem. It was always null.

I managed to solve the problem by injecting the logger in the constructor this way:

public ILogger logger;

public MyController(ILogger logger)
{
    this.logger = logger;

    logger.Info("Something");
}

回答3:

You could also initialize your Logger by using:

public ILogger Logger { get; set; }

public MyController()
{
     Logger = NullLogger.Instance;
}