Fluent NHibernate - How to map a List<IInterface> to multiple types? - fluent-nhibernate

Question

I am trying to map a list containing instances of different types that all implements a common interface with Fluent NHibernate.
Below is a simplified example of how I want my model to look like. I want all types of questions to be stored in the same table and all types of answers to be stored in one table per type.
When using the Mapping in the example for survey Nhibernate treats all questions as IQuestion, and all Answers as IAnswer
What am I doing wrong?
public class SurveyMap : ClassMap<Survey>
{
public SurveyMap()
{
Id(x => x.Id);
Map(x => x.Name);
HasMany(x => x.Questions).Cascade.All();
HasMany(x => x.Answers).Cascade.All();
}
}
public class BoolAnswerMap : SubclassMap<BoolAnswer>
{
public BoolAnswerMap()
{
Map(x => x.Value).Nullable();
References(x => x.Question);
}
}
public class DecimalAnswerMap : SubclassMap<DecimalAnswer>
{
public DecimalAnswerMap()
{
Map(x => x.Value).Nullable();
References(x => x.Question);
}
}
public class AnswerMap : ClassMap<IAnswer>
{
public AnswerMap()
{
Id(x => x.Id);
}
}
public class BoolQuestionMap : SubclassMap<BoolQuestion>
{
public BoolQuestionMap()
{
//HasMany(x => x.SubQuestions).Cascade.All(); -- Let's leave the subquestions for now
}
}
public class DecimalQuestionMap : SubclassMap<DecimalQuestion>
{
public DecimalQuestionMap()
{
}
}
public class QuestionMap : ClassMap<IQuestion>
{
public QuestionMap()
{
Id(x => x.Id);
Map(x => x.QuestionText).Not.Nullable();
DiscriminateSubClassesOnColumn("Type");
}
}
public class Survey{
private IList<IQuestion> questions = new List<IQuestion>();
private IList<IAnswer> answers = new List<IAnswer>();
public virtual string Name { get; set; }
public virtual IEnumerable<IQuestion> Questions { get { return questions; } }
public virtual IEnumerable<IAnswer> Answers { get { return answers; } }
public virtual void AddQuestion(IQuestion question){
questions.Add(question);
}
public virtual void AddAnswer(IAnswer answer{
answers.Add(answer);
}
}
public interface IQuestion{
int Id { get; set; };
string QuestionText { get; set; }
}
public interface IAnswer{
int Id { get; set; }
IQuestion Question { get; set; }
}
public class BoolQuestion: IQuestion{
private IList<IQuestion> subQuestions = new List<IQuestion>();
int Id { get; set; };
string QuestionText { get; set; }
public virtual IEnumerable<IQuestion> SubQuestions { get { return subQuestions; } }
public virtual void AddSubQuestion(IQuestion question){
subQuestions.Add(question);
}
}
//You could argue that this could be just Question (but this is a simplified example)
public class DecimalQuestion: IQuestion{
int Id { get; set; };
string QuestionText { get; set; }
}
public class BoolAnswer : IAnswer {
public int Id { get; set; }
public IQuestion Question { get; set; }
bool Value { get; set; }
}
public class DecimalAnswer : IAnswer {
public int Id { get; set; }
public IQuestion Question { get; set; }
decimal Value { get; set; }
}

Answer 1

ReferencesAny should do what you want.