<configuration>
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" />
</configSections>
<log4net>
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<lockingModel type="log4net.Appender.FileAppender+MinimalLock
 
" />
<!--日誌路徑-->
<param name="File" value="log/err/" />
<param name="Encoding" value="utf-8" />
<!--是否是向檔案中追加日誌-->
<param name="AppendToFile" value="true" />
<!--log保留天數-->
<param name="MaxSizeRollBackups" value="10" />
<!--日誌檔名是否是固定不變的-->
<param name="StaticLogFileName
 
" value="false" />
<!--日誌檔名格式為:2008-08-31.log-->
<param name="DatePattern" value="yyyy-MM-dd&quot;error.log&quot;" />
<!--日誌根據日期滾動-->
<param name="RollingStyle" value="Date" />
<layout type="log4net.Layout.PatternLayout">
<!-- <param name="Header" value="[Header] 
 
" /> -->
<conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
<!-- <param name="Footer" value="%n [Footer] " /> -->
<!-- <conversionPattern -->
<!-- value="&lt;HR COLOR=red>%n時間：%d [%t] &lt;BR>%n級別：%-5p &lt;BR>%n類：%c [%x] &lt;BR>%n%m &lt;BR>%n &lt;HR Size=1>" /> -->

</layout>
<filter type="log4net.Filter.LevelRangeFilter">
<param name="LevelMax" value="Error" />
<param name="LevelMin" value="Error" />
</filter>
</appender>

<root>
<!--(高) OFF > FATAL > ERROR > WARN > INFO > DEBUG > ALL (低) -->
<level value="all" />
<appender-ref ref="RollingLogFileAppender" />
</root>
</log4net>
</configuration>

多程序讀取檔案，會造成日誌檔案被佔用，如下：
正由另一個程序使用，因此該程序無法訪問此檔案

需要在Log4net.config新增該配置項

<lockingModel type="log4net.Appender.FileAppender+MinimalLock" />