How to use log4net in multi-dll Asp.net project?

[li nan]

Now I'm creating an Asp.net project. I create a project called COMMON,
I add the log4net.dll to this project and create an interface, so
other project can reference this COMMON.dll and use log4net directly.
But in Asp.net project, when I use this interface, no log files are generated.

How to solve this problem?

Thanks.