Give

1. using
using log4net;
using log4net.Config;

2.
#region "LogSetting"
private static readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(WMSProxy));
private void _LogSetting()
{
log4net.Config.XmlConfigurator.ConfigureAndWatch(new System.IO.FileInfo(AppDomain.CurrentDomain.BaseDirectory + "LogConfig.xml"));
}
#endregion

3. LogConfig.xml

<log4net>

<appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">

<file value="C:/tmp/log4net.log" />

<appendToFile value="true" />

<rollingStyle value="Size" />

<maximumFileSize value="2048KB" />

<maxSizeRollBackups value="5" />

<datePattern value="yyyyMMdd-HHmm" />

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

<conversionPattern value="[%date] [%level] [%logger:%line] %message%newline" />

</layout>

</appender>

<root>

<level value="DEBUG" />

<appender-ref ref="RollingFileAppender" />

</root>

</log4net>