Sunday, January 31, 2010

Using log4net with .Net 4.0 WPF Applications

I ran into some issues trying to get log4net up and running on my current project, which is being written in VS2010 Beta2, targeting the .net 4.0 framework.  I went about adding a reference to log4net, setup my app.config with a rolling log-file appender and added a call to XmlConfigurator.Configure() in one of my classes.

I then went to compile and got the following error: The type or namespace name 'log4net' could not be found (are you missing a using directive or an assembly reference?) 

I double-checked, and yes, I had indeed added a reference to log4net, so what was wrong?  Turns out, for .net 4.0 WPF projects, the default Target Framework is the “.Net Framework 4 Client Profile”, which is a subset of the full framework with the goal of shrinking footprint of the .net framework needed to download for a typical windows application.  However, log4net apparently needs access to system.web.dll, which isn’t included in the client profile. 

To fix your app so it’ll compile/run, open your project’s properties page, and set the Target Framework to “.Net Framework 4” and save your changes. 

Posted by Tony Mocella at 10:32 AM
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24 comments:

  1. Anonymous4/20/2010 3:27 PM

    thank you so much.. i was about to die in despair :)

    ReplyDelete
  2. Anonymous4/29/2010 12:12 PM

    Ok, so now no Logging on the client???

    ReplyDelete
  3. Anonymous5/16/2010 10:27 AM

    thanks a lot

    ReplyDelete
  4. Anonymous8/24/2010 4:15 PM

    Great tip.

    ReplyDelete
  5. Anonymous9/16/2010 10:25 AM

    thanks I was pulling my hair out after I rebuilt my machine.

    ReplyDelete
  6. Anonymous10/02/2010 1:35 PM

    Thanks, just a crazy bug/feature.

    ReplyDelete
  7. Anonymous10/06/2010 10:06 AM

    Thanks, what a beating that was...

    ReplyDelete
  8. Anonymous10/18/2010 10:07 AM

    Thanks for saving me a few hours! :)

    ReplyDelete
  9. Anonymous10/22/2010 9:17 AM

    Thanks!

    ReplyDelete
  10. Anonymous11/12/2010 1:26 PM

    Thanks!

    ReplyDelete
  11. Anonymous11/23/2010 8:04 AM

    Helped a lot, thank you!

    ReplyDelete
  12. Anonymous12/17/2010 10:19 AM

    thanks a lot!

    salvou meu dia!!!

    ReplyDelete
  13. Anonymous2/11/2011 3:10 PM

    You saved my day! Thanx a lot!

    ReplyDelete
  14. Anonymous3/23/2011 12:41 AM

    Thank you so much for posting this!

    ReplyDelete
  15. Anonymous4/05/2011 12:05 PM

    Thanks - i thought i was going crrrrrazy :-)

    ReplyDelete
  16. Grego de OZ4/07/2011 9:10 AM

    More detailed answer here:

    http://tseonet.blogspot.com/2010/07/making-log4net-run-on-net-40.html

    ReplyDelete
  17. Truls Unstad4/14/2011 2:20 AM

    Thank you so much for this.

    ReplyDelete
  18. Unknown6/07/2011 4:52 AM

    @Gregorio: Good call, there's an extra step for it to run that tseo seems to get. Also http://www.codeproject.com/KB/dotnet/Log4NetWithClient.aspx shows you how to build it to work for the Client Profile...

    ReplyDelete
  19. Anonymous8/05/2011 1:39 PM

    Thanks, this actually saved me. I have a 3rd party API that is a DLL and makes web service calls, so it needed the same fix. I couldn't understand why the reference was there but the messages implied they were not.

    ReplyDelete
  20. Anonymous9/27/2011 7:37 AM

    Thanks!

    ReplyDelete
  21. Anonymous11/12/2011 4:52 AM

    Thanks............!its working..........!

    ReplyDelete
  22. rss4/05/2012 4:10 AM

    Thanks a lot!!! :)

    ReplyDelete
  23. Marco5/15/2012 11:10 AM

    thanks
    after a day of unnecessary work finally your post has solved my problem
    thanks thanks thanks

    ReplyDelete
  24. Anonymous4/23/2014 6:45 AM

    Thanks yaar

    ReplyDelete

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