<PackageReference Include="System.Configuration.ConfigurationManager" Version="10.0.0-preview.7.25380.108" />

System.Configuration.SettingsSerializeAsAttribute

public sealed class SettingsSerializeAsAttribute : Attribute
Specifies the serialization mechanism that the settings provider should use. This class cannot be inherited.
public SettingsSerializeAs SerializeAs { get; }

Gets the SettingsSerializeAs enumeration value that specifies the serialization scheme.

public SettingsSerializeAsAttribute(SettingsSerializeAs serializeAs)

Initializes an instance of the SettingsSerializeAsAttribute class.