Add / remove logfiles during runtime in NLog

Question

I'm writing a small file conversion utility. Files get automatically converted when they are dropped into a directory.

I'm using NLog for logging. Besides a central log file which is configured using NLog.conf (and which receives all messages generated), I'd like to create one additional log file for each input file, having a similar name and containing all log messages written during the conversion process.

Unfortunately I seem to be unable to find out how to properly add a new file target together with the appropriate rule during runtime. I want all Logger objects to write to the new log file during the conversion process.

I tried something like

var logfile = new NLog.Targets.FileTarget(); logfile.FileName = fileName + ".log"; logfile.KeepFileOpen = true; logfile.Initialize(); var rule = new NLog.Config.LoggingRule("*", logfile); NLog.LogManager.Configuration.LoggingRules.Add(rule); NLog.LogManager.ReconfigExistingLoggers(); // // Proceed with converting file // logfile.Flush(); NLog.LogManager.Configuration.LoggingRules.Remove(rule); NLog.LogManager.ReconfigExistingLoggers(); 

But no log file was created.

What did I wrong? Any idea?

Answer 1

The second post on this thread led me to the solution: http://nlog-project.org/forum.html#nabble-td1685349

You have to get the current NLog configuration, make changes to this LoggingConfiguration object, then assign it back to LogManager.Configuration.

This is the code I used:

LoggingConfiguration config = LogManager.Configuration;  var logFile = new FileTarget(); config.AddTarget("file", logFile);  logFile.FileName = fileName + ".log"; logFile.Layout = "${date} | ${message}";  var rule = new LoggingRule("*", LogLevel.Info, logFile); config.LoggingRules.Add(rule);  LogManager.Configuration = config;  logger.Info("File converted!");