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

System.Configuration.SettingsPropertyIsReadOnlyException

Provides an exception for read-only SettingsProperty objects.
namespace System.Configuration { public class SettingsPropertyIsReadOnlyException : Exception { public SettingsPropertyIsReadOnlyException(string message); public SettingsPropertyIsReadOnlyException(string message, Exception innerException); protected SettingsPropertyIsReadOnlyException(SerializationInfo info, StreamingContext context); public SettingsPropertyIsReadOnlyException(); } }