App. Config "configuration system failed to initialize" exception Resolution C #

system.configuration.configurationmanager.appsettings["User"];

" configuration system failed to initialize" error occurred

Workaround:

If the configuration file contains a configsections element, the configsections element must be the first child element of the configuration element. ", after placing the appsettings in configsections, it is normal.

It's a question of calling log4net and messing up the app. config order.

<?xml version= "1.0" encoding= "Utf-8"?><configuration> <configSections> <!--log4net definition-- <section name= "log4net" type= "log4net. Config.log4netconfigurationsectionhandler, log4net "/> </configSections> <startup> <supported Runtime version= "v4.0" sku= ". netframework,version=v4.0 "/> </startup> <!--configuration log4net--> <log4net> <!--logging by days using rolling method Logs--<appender name= "errorlog" type= "log4net. Appender.rollingfileappender "> <file value=" log\\ "/> <appendtofile value=" true "/> <para M name= "Lockingmodel" value= "log4net. Appender.FileAppender.MinimalLock "/> <rollingstyle value=" Date "/> <datepattern value=" Yyyy-mm-dd ". TXT ""/> <staticlogfilename value= "false"/> <layout type= "log4net. Layout.patternlayout "> <!--
　　
App. Config "configuration system failed to initialize" exception Resolution C #