c# - Throw a ConfigurationErrorsException when run .net app on ubuntu with mono4 -

i wrote , compiled helloworld app in vs2015rc:

namespace test {     class program     {         protected static readonly namevaluecollection appsettings = configurationmanager.appsettings;         private static readonly string rootdir = appsettings["rootdirpath"] ?? "";          static void main(string[] args)         {             console.writeline("hello world");             console.writeline(rootdir);             console.readkey();         }     } } 

when run app on on ubuntu mono4, configurationerrorsexception thrown:

lijing@ubuntu:~/desktop/iqq.net$ mono test.exe

unhandled exception: system.typeinitializationexception: exception thrown type initializer test.program system.configuration.configurationerrorsexception: error initializing configuration system. system.configuration.configurationerrorsexception: unrecognized configuration section (/home/lijing/desktop/iqq.net/test.exe.config line 3)

this config file:

<?xml version="1.0" encoding="utf-8" ?> <configuration>   <appsettings>     <add key="rootdirpath" value="xxxxxxxxxxxxxxxxxxxx"/>     <add key="libpath" value="lib\win64\"/>     <add key="datadirpath" value=""/>   </appsettings> </configuration> 

the mono version is: mono jit compiler version 4.0.2 (stable 4.0.2.5/c99aa0c wed jun 24 10:04:37 utc 2015)