(.NET) 다른 config 파일 읽어오기

ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();
fileMap.ExeConfigFilename = configFileName;

Configuration configuration = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
ConnectionStringsSection conStrSection = configuration.ConnectionStrings as ConnectionStringsSection;

foreach (ConnectionStringSettings con in conStrSection.ConnectionStrings)

{
}

configuration.AppSettings.Settings.AllKeys.GetEnumerator();

configuration.AppSettings.Settings["TEST"].Value.ToString();