Log4net: How to enable debug logging at runtime?

问题

In the test environment, the debug log is enabled, so I can see detailed debug log messages. In production environment, I want to disable debug log by default, but still want to enable/disable it if needed.

Can I enable debug log at runtime without restarting my application? My logging code looks like below:

if(logger.IsDebugEnabled) Logger.Debug("debug message");

回答1:

You can change to loglevel by setting it and then apply the new settings:

((log4net.Repository.Hierarchy.Hierarchy)LogManager.GetRepository()).Root.Level = Level.Debug;
((log4net.Repository.Hierarchy.Hierarchy)LogManager.GetRepository()).RaiseConfigurationChanged(EventArgs.Empty);

回答2:

Normal way of doing this is to get log4net to Watch for changes to the app.config or configuration file.

eg use the attribute

[assembly: log4net.Config.XmlConfigurator(Watch=true)]

or

log4net.Config.XmlConfigurator.ConfigureAndWatch(new  System.IO.FileInfo(logConfigFilename));

and the default config can be configured to set logging off.

Then any changes to your config file will take effect immediately without you need to restart your program.

来源：https://stackoverflow.com/questions/40176935/log4net-how-to-enable-debug-logging-at-runtime