一、程序集加载
[assembly: log4net.Config.XmlConfigurator(ConfigFile = @"Config\log4net.config", Watch = true)]
二、配置文件
<?xml version="1.0" encoding="utf-8" ?>
<log4net>
<appender name="errorAppender" type="log4net.Appender.RollingFileAppender">
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="ERROR" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<file value="Logs\error.log" />
<encoding value="utf-8"/>
<preserveLogFileNameExtension value="true" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<datePattern value="yyyyMMdd" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level - %message%newline" />
</layout>
</appender>
<appender name="infoAppender" type="log4net.Appender.RollingFileAppender">
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="INFO" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<file value="Logs\info.log" />
<encoding value="utf-8"/>
<preserveLogFileNameExtension value="true" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<datePattern value="yyyyMMdd" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level - %message%newline" />
</layout>
</appender>
<appender name="debugAppender" type="log4net.Appender.RollingFileAppender">
<filter type="log4net.Filter.LevelMatchFilter">
<levelToMatch value="DEBUG" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />
<file value="Logs\debug.log" />
<encoding value="utf-8"/>
<preserveLogFileNameExtension value="true" />
<appendToFile value="true" />
<rollingStyle value="Date" />
<datePattern value="yyyyMMdd" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%date [%thread] %-5level - %message%newline" />
</layout>
</appender>
<root>
<level value="ALL" />
<appender-ref ref="errorAppender" />
<appender-ref ref="infoAppender" />
<appender-ref ref="debugAppender" />
</root>
</log4net>
原文地址：https://www.cnblogs.com/ljsoftware/p/9050295.html