<PackageReference Include="System.Configuration.ConfigurationManager" Version="10.0.0-preview.4.25258.110" />

ConfigurationSectionGroup

namespace System.Configuration { public sealed class ClientSettingsSection : ConfigurationSection { private static readonly ConfigurationProperty s_propSettings; private static readonly ConfigurationPropertyCollection s_properties; protected internal override ConfigurationPropertyCollection Properties { get { return s_properties; } } [ConfigurationProperty("", IsDefaultCollection = true)] public SettingElementCollection Settings { get { return (SettingElementCollection)base[s_propSettings]; } } public ClientSettingsSection() { base..ctor(); } static ClientSettingsSection() { s_propSettings = new ConfigurationProperty(null, Type.GetTypeFromHandle(typeof(SettingElementCollection).TypeHandle), null, ConfigurationPropertyOptions.IsDefaultCollection); s_properties = new ConfigurationPropertyCollection { s_propSettings }; } } }