NLog引用项目没有日志输出

Question

I am using NLog 4.5.11 in one Visual Studio 2017 solution. It has the nlog.config in the start up project, but the actual logging required is from another project, where NLog is referenced (but no nlog.config exists). Running this solution works fine, the NLog logs are being produced where I expect.

The second VS solution uses (references) both the start up project and the one with the logging. One note on this project is that it is an Excel Add-on. When I run (debug from VS) this second solution, I do NOT get the NLog logging that should have been triggered via the referenced projects' code and NLog logging. I do not get any errors, exceptions, or error files etc.

I have tried also installing the NuGet packages for NLog to the second solution. I also tried adding a copy of the nlog.config to it. I have looked in the build directory and the NLog dlls and config file are being copied there. I have also tried enabling the throwExceptions="true" and internalLogLevel="Trace".

I have been looking on SO and elsewhere, but I cannot find a solution or even how to debug it. All that ever happens is simply no output, which is really frustrating.

NLog.config

<?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"
      xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd"
      autoReload="true"
      throwExceptions="true"
      internalLogLevel="Trace" internalLogFile="c:\temp\nlog-internal.log">

  <variable name="appName" value="FSIS" />
  <variable name="logDir" value="c:\temp\Rbnz.Fsis.Logging" />
  <variable name="logDirArchive" value="c:\temp\Archive\Rbnz.Fsis.Logging" />

  <targets async="true">
    <target xsi:type="File"
            name="default"
            layout="${longdate} - ${level:uppercase=true}: ${message}${onexception:${newline}EXCEPTION\: ${exception:format=ToString}}"
            fileName="${logDir}\${shortdate}.log"
            keepFileOpen="false"
            archiveFileName="${logDirArchive}\${shortdate}.{##}.log"
            archiveNumbering="Sequence"
            archiveEvery="Day"
            maxArchiveFiles="30"
    />
  </targets>
  <rules>
    <logger name="*" writeTo="default" minlevel="Debug" />
  </rules>
</nlog>

Usage inside the code of the referenced project:

private static NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();

and later on, inside a method:

logger.Info("Start: CompileSeries()");
logger.Info("Done: CompileSeries()");

I expected that if NLog logging works for a project, then including that project as a reference in another project (in another solution), would trigger the same logging. Obviously I'm incorrect in this assumption.

Answer 1

Based on what you wrote, you have a First Solution that has two projects--a startup project that configures a logger object. That solution has a second project that references the startup project's logger object. Fine.

Now you have a Second Solution. In this solution, you simply reference the First Solution's startup project assembly and the First Solution's second project. Your Second Solution has its own project that's trying to access the logger exposed by the First Solution's referenced projects.

This issue is that your First Solution actually executes its startup project . Your Second Solution does not execute it--it simply references it . Therefore, your logger object isn't getting properly initialized by NLog.

The solution (generically) is to ensure that your logger object is initialized in your Second Solution just as it's initialized in your First Solution. If you want more specific guidance, show specifics as to how your First Solution's startup project initializes the logger object and I should be able to help you replicate that logic in the Second Solution.

Your conclusion that you cannot log from another solution is incorrect. It's all about proper object initialization.

I hope this helps.