应用程序在修改Log4net的App.config时崩溃

Question

This is my first time ever using Log4Net so I'm sure I'm doing something really dumb.

In App.config , inside the <configuration> tag, I have the following:

<log4net>
   <appender name="LogFileAppender" type="log4net.Appender.FileAppender">
     <param name="File" value="log-file.txt" />
     <param name="AppendToFile" value="true" />
     <layout type="log4net.Layout.PatternLayout">
        <param name="Header" value="[Header]\r\n" />
        <param name="Footer" value="[Footer]\r\n" />
        <param name="ConversionPattern" value="%d [%t] %-5p %c [%x] &lt;%X{auth}&gt; - %m%n" />
     </layout>
   </appender>

   <root>
     <level value="WARN" />
        <appender-ref ref="LogFileAppender" />
   </root>
</log4net>

In my Program.cs file I catch a ConfigurationException:

Message: Configuration system failed to initialize
InnerException: Unrecognized configuration section log4net.

But I copy-pasted the configuration code straight out of the .NET example they provide on their website. I read over their documentation but it's pretty confusing for someone who has never used any sort of logging framework before. I also found a few tutorials on CodeProject that hold your hand better but can't piece out what I've done wrong. I tried putting the <root> element before the <appender> element and that gives me the same ConfigException. And yes I've added a reference to the DLL to the project.

Answer 1

Sounds like you just forgot to include the configSection entry for log4net :

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

    <!-- other configurations, such as appSettings and whatnot -->

    <log4net>
        <!-- log4net configuration that you already have -->
    </log4net>
</configuration>

In order to use the log4net config node the system needs to be told how to interpret that node, which is handled in the log4net.Config.Log4NetConfigurationSectionHandler class.