您可以通过应用过滤器，以一个appender做到这一点。只有当日志事件通过过滤器并在事件得到由该附加器记录下来。

You can do this by applying a filter to an appender. Only if the log event passes the filter does the event get logged by that appender.

此过滤器的配置将只记录那些事件从一个名为MyLogger记录器来了：

This filter configuration will log only those events coming from the logger named "MyLogger":

<appender name="EventLogAppender" ...
    <filter type="log4net.Filter.LoggerMatchFilter">
        <loggerToMatch value="MyLogger" />
    </filter>   	
    <filter type="log4net.Filter.DenyAllFilter" />
</appender>

...而这一次将匹配记录与特定包含的短信：

...and this one will match log messages with certain contained text:

<filter type="log4net.Filter.StringMatchFilter">
    <stringToMatch value="database" />
</filter>
<filter type="log4net.Filter.DenyAllFilter" />

有配置可能带过滤器的好一点。请参阅 log4net的SDK ，或manual ，了解更多信息。

There's a good bit of configuration possible with filters. See the log4net SDK, or the Filters section of the manual, for more details.