Question

I’m trying to customise a log4net file path to use a property I have set in the log4net.GlobalContext.Properties dictionary.

log4net.GlobalContext.Properties['LogPathModifier'] = 'SomeValue'; 

I can see that this value is set correctly when debugging through it. and then in my configuration

<file type='log4net.Util.PatternString'        value='Logs\%appdomain_%property{LogPathModifier}.log' /> 

However, the output of this gives me ‘_(null).log’ at the end of the path. What gives?

Answer 1

I ran into the same behavior and solved it by setting the global variable before calling the XmlConfigurator… Here is what I am successfully using:

log4net.config details:

<appender name='RollingLogFileAppender' type='log4net.Appender.RollingFileAppender,log4net'>   <File type='log4net.Util.PatternString' value='App_Data/%property{LogName}' />   ... </appender> 

Global.asax details:

private static readonly log4net.ILog log = log4net.LogManager.GetLogger('Global.asax'); void Application_Start(object sender, EventArgs e)  {     // Set logfile name and application name variables     log4net.GlobalContext.Properties['LogName'] = GetType().Assembly.GetName().Name + '.log';     log4net.GlobalContext.Properties['ApplicationName'] = GetType().Assembly.GetName().Name;      // Load log4net configuration     System.IO.FileInfo logfile = new System.IO.FileInfo(Server.MapPath('log4net.config'));     log4net.Config.XmlConfigurator.ConfigureAndWatch(logfile);      // Record application startup     log.Debug('Application startup'); } 

Hope this helps…