参数到 LogManager.GetLogger

为什么大多数 log4net 示例通过以下方法获得类的日志记录器:

private static ILog logger =
LogManager.GetLogger(
System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

而不是仅仅传递 typeof (MyClass) :

private static ILog logger = LogManager.GetLogger(typeof(MyClass));

除了第一个选项不要求您键入特定的类名之外，还有其他原因吗？

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As you say - its convenient as you can create a logger in a method without knowing the name of the class (trivial I know) but allows you to cut and paste methods between classes without having to rename the call.

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最佳答案

I think you've got the reason. I do it that way so I don't have to worry about the class name and can just copy and paste boiler plate code in a new class.

For the official answer, see: How do I get the fully-qualified name of a class in a static block? at the log4net faq

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I think the reason is, that you get the type of the runtime type using the .DeclaringType() method. You can use the logger in a base class and still see the actual type of your object in the loggers output. That makes investigations much more convinient.

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I'm an NLog user, and usually this boils down to :

var _logger = LogManager.GetCurrentClassLogger();

It seemed a bit strange that you need to go through reflection in Log4Net, so I had a look in the NLog source code, and lo and behold, this is what they do for you:

[MethodImpl(MethodImplOptions.NoInlining)]
public static Logger GetCurrentClassLogger()
{
string loggerName;
Type declaringType;
int framesToSkip = 1;
do
{
#if SILVERLIGHT
StackFrame frame = new StackTrace().GetFrame(framesToSkip);
#else
StackFrame frame = new StackFrame(framesToSkip, false);
#endif
var method = frame.GetMethod();
declaringType = method.DeclaringType;
if (declaringType == null)
{
loggerName = method.Name;
break;
}
framesToSkip++;
loggerName = declaringType.FullName;
} while (declaringType.Module.Name.Equals("mscorlib.dll", StringComparison.OrdinalIgnoreCase));
return globalFactory.GetLogger(loggerName);
}

I guess I would write something similar for Log4Net as an extension or static method instead of pasting the reflection as part of my boiler code :)

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It also makes it easier to create Codesmith templates for code generation purposes.

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The following portable solution worked for me in .NET Core 6:

private static readonly ILog _log = LogManager.GetLogger(MethodBase.GetCurrentMethod()?.DeclaringType);

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