log4net config

app.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
  </configSections>
  <!-- .... -->
  <log4net>
    <root>
      <level value="DEBUG" />
      <appender-ref ref="RollingFileAppender" />
      <appender-ref ref="ConsoleAppender" />
    </root>
    <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
      <appendToFile value="true" />
      <rollingStyle value="Date" />
      <datePattern value="yyyyMMdd" />
      <file type="log4net.Util.PatternString" value="C:\\Path\\To\\My\\Logs\\app_.txt" />
      <preserveLogFileNameExtension value="true"/>
      <staticLogFileName value="false" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
      </layout>
    </appender>
    <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender">
      <param name="Threshold" value="INFO" />
      <layout type="log4net.Layout.PatternLayout">
        <param name="ConversionPattern" value="%d [%t] %-5p %c [%x] - %m%n" />
      </layout>
    </appender>
  </log4net>
  </configuration>

Program.cs

log4net.Config.XmlConfigurator.Configure();