如何在app.config中设置EnterpriseLibrary.Logging的日志严重级别？

我负责维护一个开发已久的Windows Service，原作者早已离职。我希望将日志严重级别从Information提升至Warning以减少事件日志记录，但在app.config中未找到可限制日志写入严重级别的配置项，附上当前配置代码，恳请使用过该方案的开发者指导配置方法。

当前app.config日志配置 #

<configSections>
    <section name="loggingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.LoggingSettings, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true"/>
    <sectionGroup name="applicationSettings" type="System.Configuration.ApplicationSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <section name="CompanyName0PBR_Service.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false"/>
    </sectionGroup>
  </configSections>
  <loggingConfiguration name="" tracingEnabled="true" defaultCategory="General">
    <listeners>
      <add name="Event Log Listener" type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
     listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FormattedEventLogTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
     source="PBRProcessing" formatter="Text Formatter" log="CompanyName0PKPBR_Service" machineName="." traceOutputOptions="None" />
    </listeners>
    <formatters>
      <add type="Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.TextFormatter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" template="Message: {message}{newline}" name="Text Formatter"/>
    </formatters>
    <categorySources>
      <add switchValue="All" name="General">
        <listeners>
          <add name="Event Log Listener"/>
        </listeners>
      </add>
    </categorySources>
    <specialSources>
      <allEvents switchValue="Off" name="All Events"/>
      <notProcessed switchValue="Off" name="Unprocessed Category"/>
      <errors switchValue="Off" name="Logging Errors &amp; Warnings">
        <listeners>
          <add name="Event Log Listener"/>
        </listeners>
      </errors>
    </specialSources>
  </loggingConfiguration>

针对Enterprise Library 5.0的日志配置，你需要修改categorySources节点下对应分类的switchValue属性：

• 当前你的General分类的switchValue是All，这意味着会记录所有级别的日志
• 将其修改为Warning，这样就只会记录Warning及更高级别的日志（包含Error、Critical等），从而过滤掉Information级别的日志

修改后的categorySources节点如下：

<categorySources>
  <add switchValue="Warning" name="General">
    <listeners>
      <add name="Event Log Listener"/>
    </listeners>
  </add>
</categorySources>

补充说明 #

switchValue的可选值按级别从高到低为：

• Off：完全关闭日志
• Critical：仅记录严重错误
• Error：记录错误及Critical
• Warning：记录警告及Error、Critical
• Information：记录信息及以上级别
• Verbose：记录详细日志及以上
• All：记录所有级别日志

内容的提问来源于stack exchange，提问作者Circle Hsiao