====== Log4net Setup ======

===== AssemblyInfo.cs =====

<code c#>
// Configure log4net using the .config file
[assembly: log4net.Config.XmlConfigurator(Watch=true)]
// This will cause log4net to look for a configuration file
// called TestApp.exe.config in the application base
// directory (i.e. the directory containing TestApp.exe)
// The config file will be watched for changes.
</code>

===== App.config =====

This file is named 'app.config' in the source. Visual Studio seems to rename this to 'ApplicationName.exe.config' when it is copied to the bin directory during compilation.

<code xml>
<?xml version="1.0"?>
<configuration>
	<configSections>
		<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
	</configSections>
	<log4net>
		<appender name="FileAppender" type="log4net.Appender.FileAppender">
			<file value="log-file.txt" />
			<appendToFile value="true" />
			<layout type="log4net.Layout.PatternLayout">
				<conversionPattern value="%date{yyyy-MM-dd HH:mm:ss.fff},%thread,%logger,%level,%message%newline" />
			</layout>
		</appender>
		<root>
			<level value="DEBUG" />
			<appender-ref ref="FileAppender" />
		</root>
	</log4net>
</configuration>
</code>

To roll the log files, use something like this:

<code xml>
<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
	<file value="log-file.txt" />
	<appendToFile value="true"/>
	<immediateFlush value="true"/>
	<maxSizeRollBackups value="100"/>
	<rollingStyle value="Size"/>
	<maximumFileSize value="10Mb"/>
	<layout type="log4net.Layout.PatternLayout">
		<conversionPattern value="%date{yyyy-MM-dd HH:mm:ss.fff},%thread,%logger,%level,%message%newline" />
	</layout>
</appender>
</code>

To specify only certain loggers:

<code xml>
<appender ...>
	...
	<filter type="log4net.Filter.LoggerMatchFilter">
		<loggerToMatch value="GeneralLog"/>
	</filter>
	<filter type="log4net.Filter.DenyAllFilter"/>
</appender>
</code>

To remove certain loggers:

<code xml>
<log4net>
	...
	<root>
		...
	</root>
	<logger name="GeneralLog">
		<level value="Off" />
	</logger>
</log4net>
</code>

To switch off all logging:

<code xml>
<log4net threshold="OFF" />
</code>

===== Logger.cs =====

<code c#>
namespace FooBar
{
	using log4net;

	internal static class Logger
	{
		private static ILog _general;
		internal static ILog General
		{
			get
			{
				if (_general == null)
				{
					_general = LogManager.GetLogger("General");

					// Ensure the logger gets configured.
					log4net.Config.XmlConfigurator.Configure();
				}

				return _general;
			}
		}
	}
}
</code>

===== Levels =====

  * Off
  * Fatal
  * Error
  * Warn
  * Info
  * Debug
  * All

{{tag>log4net reference}}