Actually, the file attribute on the <log4net> node is processed by the
.NET framework as a redirection to the given file.  The attribute tells
.NET to look for the actual definition of the section in the given file.
log4net should be oblivious to this but it is not.


The behavior seen is that log4net does read its configuration
information from the specified file *but* it doesn't recognize those
standard XML tags we log4net users have come to know and love.   All it
recognizes is <param . . . />.   Of course, one could work around
this--no functionality is prevented by this behavior--but it is rather
awkward and unfriendly to work that way (especially if you're trying to
do something like use schema directives for "intellisense"-like help).

It is also much more readable to use the standard log4net schema and
understandable to people who come onboard the project from other
projects which have also used log4net.


The take-away from this experience for me is that web.config
redirections do not work nicely for log4net configuration. Though one
can make them work, they exact a penalty.  Better it is to just directly
name that separate log4net config file when one initializes log4net.


BTW,   the best "intellisense" log4net schema I have found so far is
from and is expressed as follows:





If there is another one better, I would like to hear about it.
Specifically, it would be nice if I could find such a schema at !


 == Eric ==


From: Ron Grabowski [] 
Sent: Friday, June 19, 2009 1:49 PM
To: Log4NET User
Subject: Re: Mystery concerning configuration SOLVED.


Log4net doesn't process the file attribute. I'm not sure how you're
using it. These two nodes are processed identically during

 <param name="Hello" value="World" />
 <Hello value="World "/>


From: Eric Chamberlain <>
To: Log4NET User <>
Sent: Friday, June 19, 2009 12:56:34 PM
Subject: RE: Mystery concerning configuration SOLVED.

I have discovered the source of the problem.   We had split out the
<log4net> configuration from the web.config but with a redirection left
inside the web.config of the form:


<log4net  file="other_config_directory/log4net.config" />


The file at the end was of the correct syntax and could be used by
log4net but only to the extent that we used the <param...>  elements.  


I have modified the program to initialized log4net directly from the
split-out file and it works with full syntactical support.


Go figure, eh?


  == Eric ==



From: Eric Chamberlain <>
Sent: Thursday, June 18, 2009 6:41:51 PM
Subject: Mystery concerning configuration

Greetings all,


I have an appender which works fine if specified with generic XML but
not when specified with conventional log4net terms in the configuration.


Examples should help:


The following works:


  <appender name="LogServiceAppender"


    <param name="File"

           value="myfile.log" />

    <param name="AppendToFile"

           value="true" />

    <param name="MaxSizeRollBackups"


    <param name="MaximumFileSize"


    <param name="RollingStyle"


    <param name="StaticLogFileName"


    <layout type="log4net.Layout.PatternLayout">

      <param name="ConversionPattern"

             value="%d{yyyy MMM dd HH:mm:ss} [%t] %-5p - %m%n" />




But the following does *not* work.  It fails to initialize (I turned on
the log4net debugging to see it).


  <appender name="LogServiceAppender"


    <file value="myfile.log" />

    <appendToFile value="true"/>

    <maxSizeRollBackups value="10"/>

    <maximumFileSize value="1MB"/>

    <rollingStyle value="Size"/>

    <staticLogFileName value="true"/>

    <layout type="log4net.Layout.PatternLayout">

      <conversionPattern value="%d{yyyy MMM dd HH:mm:ss} [%t] %-5p -
%m%n" />




It appears that log4net initialization does not recognized its own XML
schema.   How is that possible?  


Eric Chamberlain

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