The ConfigSource property represents the value of the configSource attribute that is specified for a ConfigurationSection object that is associated with the SectionInformation object.
A ConfigurationSection implementation can optionally specify a separate file in which the configuration settings for that section are defined. This can be useful in multiple ways:
Using include files can result in a more logical and modular structure for configuration files.
File-access security and permissions can be used to restrict access to sections of configuration settings.
Settings in an include file that are not used during application initialization can be modified and reloaded without requiring an application restart.
The following example shows how this attribute is used in a configuration file to specify that the pages section is defined in an external include file:
<pages configSource="pages.config"/>
If any of the settings in a configuration include file require the application to restart when they are modified, set the RestartOnExternalChanges property to true.