添加要包含在所有log4net消息中的自定义属性

 <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
</configSections>

<log4net>
  <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
    <file value="log-file.txt" />
   <appendToFile value="true" />
   <rollingStyle value="Size" />
    <maxSizeRollBackups value="10" />
   <maximumFileSize value="10MB" />
   <staticLogFileName value="true" />
   <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date [%thread] %-5level %logger [%property{customProperty}] - %message%newline" />
    </layout>
  </appender>
  <root>
   <level value="INFO" />
    <appender-ref ref="RollingFileAppender" />
  </root>
</log4net>

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

private static readonly ILog log = LogManager.GetLogger(typeof(YourClassName));

ThreadContext.Properties["customProperty"] = "yourCustomValue";