This .NET enum wraps the AcGiViewportTraits.DefaultLightingType ObjectARX enum. 

Enumerates the types of default lights available for viewports and full renders. One of these types is used when no user lights are specified, or when user lights are overridden by a call to SetDefaultLightingOn().

Public Enum DefaultLightingType
  OneDistantLight
  TwoDistantLights
End Enum

public enum DefaultLightingType {
  OneDistantLight,
  TwoDistantLights
}