如何告诉NLog有选择地登录到两个不同的内存目标？

Question

I have a class with an NLog MemoryTarget. I have the need for each instance of the class that the logs from that instance goes to its MemoryTarget aggregated instance.

I use SimpleConfigurator.ConfigureForTargetLogging(instance.MemoryTarget, LogLevel.Trace) to initialise the logger, which causes the last ConfigureForTargetLogging call on the last instance to direct all logging to the last instance's MemoryTarget.

The MemoryTarget can be instantiated with a name, but I'm not sure I have a way to create a logger instance that sends to that named target only.

Answer 1

You can use logger name filters in rules: Do not forger final keyword that quit processing any further rule when this one matches:

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

  <targets>
    <target name="perf" xsi:type="File" fileName="perf.log" />
    <target name="console" xsi:type="Console" />
  </targets>

  <rules>
    <logger name="Perf" minlevel="Info" writeTo="perf.log" final="true" />
    <logger name="*" minlevel="Debug" writeTo="console" />
  </rules>
</nlog>

Programmatically:

var config = new NLog.Config.LoggingConfiguration();

var logfile = new NLog.Targets.FileTarget() { FileName = "perf.log", Name = "perf" };
var console = new NLog.Targets.ConsoleTarget() { Name = "console" };

config.LoggingRules.Add(new NLog.Config.LoggingRule("Perf", LogLevel.Info, perf)){Final="true"};
config.LoggingRules.Add(new NLog.Config.LoggingRule("*", LogLevel.Debug, console));

NLog.LogManager.Configuration = config;

in your code you can get named logger:

Logger logger = NLog.LogManager.GetLogger("Perf")