Autofac:注册组件并根据解析父组件进行解析 [英] Autofac: Register component and resolve depending on resolving parent
问题描述
我想注册一个组件以根据它可能要解析的类使用参数进行解析.(这听起来有点令人困惑,所以我会举一个例子).
I'm wanting to register a component to resolve with parameters based on the class that it might be resolving for. (That sounds a bit confusing, so I'll show an example).
这是一个使用记录器的对象:
Here's an object that uses a logger:
class MyObject : IMyObject
{
public ILogger Logger;
public MyObject(ILogger logger)
{
Logger = logger;
}
}
现在传入的记录器可能因类而异.因此,对于如何在下面执行此操作,我有一个相当完整的想法:
Now the logger that is passed in COULD be different from class to class. So I've got a rather patched idea for how to do that below:
class MyLogger : ILogger
{
public string Name{get; protected set;}
public static ILogger GetLogger(string className)
{
Name = className;
MyLogger logger;
// Do something to choose a logger for that specific class
return logger;
}
}
所以当我注册 Logger 时,我希望能够告诉它 className.我希望有一种方法可以做到与此类似:
So when I register Logger I want to be able to tell it the className. I'm hoping there's a way to do it similar to this:
ContainerBuilder builder = new ContainerBuilder();
builder.Register<MyLogger>(ctx =>
{
string className = //Get resolving class name somehow;
return MyLogger.GetLogger(className);
}).As<ILogger>();
builder.Register<MyObject>().As<IMyObject>();
var container = builder.Build();
IMyObject myObj = container.Resolve<IMyObject>();
//myObject.Logger.Name should now == "MyObject"
我想这样做的原因是为了避免在代码中使用带有 autofac 的记录器注册我实现的每个类.我希望能够在 xml 中注册所有对象,并且只需要一个 LoggerModule 来添加此注册.
The reason I want to do it this way is to avoid registering each class I implement with a logger with autofac in code. I want to be able to register all of the objects in xml, and simply have a LoggerModule, that adds this registration.
提前致谢!
推荐答案
这是我所做的(ILog 只是我自己的 log4net 包装器):
Here's what I do (ILog is just my own wrapper around log4net):
public class LoggingModule : Module
{
protected override void Load(ContainerBuilder builder)
{
builder.Register((c, p) => GetLogger(p.TypedAs<Type>()));
}
protected override void AttachToComponentRegistration(
IComponentRegistry registry, IComponentRegistration registration)
{
registration.Preparing +=
(sender, args) =>
{
var forType = args.Component.Activator.LimitType;
var logParameter = new ResolvedParameter(
(p, c) => p.ParameterType == typeof (ILog),
(p, c) => c.Resolve<ILog>(TypedParameter.From(forType)));
args.Parameters = args.Parameters.Union(new[] {logParameter});
};
}
public static ILog GetLogger(Type type)
{
return new Log4NetLogger(type);
}
}
public interface ILog
{
void Debug(string format, params object[] args);
void Info(string format, params object[] args);
void Warn(string format, params object[] args);
void Error(string format, params object[] args);
void Error(Exception ex);
void Error(Exception ex, string format, params object[] args);
void Fatal(Exception ex, string format, params object[] args);
}
public class Log4NetLogger : ILog
{
private readonly log4net.ILog _log;
static Log4NetLogger()
{
XmlConfigurator.Configure();
}
public Log4NetLogger(Type type)
{
_log = LogManager.GetLogger(type);
}
public void Debug(string format, params object[] args)
{
_log.DebugFormat(format, args);
}
public void Info(string format, params object[] args)
{
_log.InfoFormat(format, args);
}
public void Warn(string format, params object[] args)
{
_log.WarnFormat(format, args);
}
public void Error(string format, params object[] args)
{
_log.ErrorFormat(format, args);
}
public void Error(Exception ex)
{
_log.Error("", ex);
}
public void Error(Exception ex, string format, params object[] args)
{
_log.Error(string.Format(format, args), ex);
}
public void Fatal(Exception ex, string format, params object[] args)
{
_log.Fatal(string.Format(format, args), ex);
}
}
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