ConfigurationSectionCollection contains many system names besides my custom section

Here is my config file:

<?xml version="1.0" encoding="utf-8" ?><configuration><configSections><section name="MySection" type="MyApp.MySectionClass, MyApp"/></configSections><MySection name="SomeName" data_type="SomeDataType" file_name="file">	<CollectionName><add name="name1" param="-10" ping="3"/><add name="name1" param="-10" ping="5"/><add name="name2" param="-10" ping="3" param2="0.3" param3="0.2"/></CollectionName></MySection ></configuration>

Here is the code where i try just to have a list of my names of sections in my config file:

ExeConfigurationFileMap map = new ExeConfigurationFileMap();
map.ExeConfigFilename = "path\\app.config";
Configuration config = ConfigurationManager.OpenMappedExeConfiguration(map, ConfigurationUserLevel.None);
ConfigurationSectionCollection section_collection = config.Sections;

foreach (string key in section_collection.Keys) Console.WriteLine(key);

Here what i get as a result:

system.data.sqlclient
connectionStrings
system.webServer
system.data.dataset
satelliteassemblies
mscorlib
startup
runtime
appSettings
system.data.odbc
system.data
configProtectedData
system.codedom
uri
system.runtime.remoting
assemblyBinding
windows
system.data.oracleclient
MySection
system.windows.forms
system.diagnostics
system.data.oledb

As you can see there is my section name, but also a lot of other namespaces. Why does it happen? How can i get only my custom sections from app.config? I don't know sections' names and number of them beforehand. That's why i want to iterate over the section collection.

Thanks.