c# - Log4net doesn't write to file

Question

I want add new log to file.this is my appender:

<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
  <file value="mylogfile.txt"/>
  <appendToFile value="true"/>
  <rollingStyle value="Size"/>
  <maxSizeRollBackups value="5"/>
  <maximumFileSize value="10MB"/>
  <staticLogFileName value="true"/>
  <filter type="log4net.Filter.StringMatchFilter">
    <stringToMatch value="test"/>
  </filter>
  <filter type="log4net.Filter.StringMatchFilter">
    <stringToMatch value="error"/>
  </filter>
  <filter type="log4net.Filter.DenyAllFilter"/>
  <layout type="log4net.Layout.PatternLayout">
    <conversionPattern value="%date [%thread] %level %logger - %message%newline%exception"/>
  </layout>
</appender>
<root>
  <level value="All"/>
  <appender-ref ref="RollingFileAppender"/>
</root>

and on my class I add

[assembly: XmlConfigurator(Watch = true)]

and I add access everyone for the file but: log4net doesn't write to file. Why?

Answer 1

Log4net fails silently when there's a problem. The design conceit is that no logging is preferable to taking down the application. To figure out what's wrong, turn on Log4net's internal debugging by adding this key to your [app/web].config file:

<appSettings>
  <add key="log4net.Internal.Debug" value="true"/>
</appSettings>

The debug messages will be written to the console or to the System.Diagnostics.Trace system. More details from Phill Haack at http://haacked.com/archive/2006/09/26/Log4Net_Troubleshooting.aspx/

There are any number of reasons Log4net might fail. Permissions problems on the log file directory, for starters (especially true for server processes, where your likely running under a restricted set of permissions for security).