Mapping a collection of entities in fluent nHibernate - nhibernate

Question

I'm developing a question/answer based application
I have a Post table in the db along the lines of:
ID
Title
Body
DateCreated
AuthorID
AuthorName (in case user not registered)
AutherEmail (as above)
PostType (enum - 1 if question, 2 if reply)
Show (bit field)
Then, there is "PostBase" - which is an abstract class (this has properties common to both Question and Answer - listed below)
I then have an internal "Post" class, which descends from PostBase, and therefore has all the properties listed above.
There is then have a Question class, and an Answer class.
Both use Post as a base class.
Here are the classes:
public abstract class PostBase
{
{
get { return postCreatorEmail; }
//todo: add email address validation here?
set { postCreatorEmail = value; }
} private IList<Attachment> attachments = new List<Attachment>();
public PostBase()
{
//init logic here
}
public virtual DateTime DateCreated { get; set; }
public virtual string ID { get; set; }
public virtual string Body { get; set; }
public virtual DateTime DateLastModified { get; set; }
public virtual string PostCreatorName { get; set; }
public virtual string PostCreatorEmail { get; set; }
public virtual int PostCreatorID { get; set; }
public virtual PostType PostType { get; set; }
public virtual PostSource PostSource { get; set; }
public virtual bool Show { get; set; }
public IEnumerable<Attachment> Attachments { get { return attachments; } }
}
Post
internal class Post : PostBase
{
public virtual List<string> Tags { get; set; }
public virtual string Title { get; set; }
public virtual string ParentPostID { get; set; }
}
Question:
public class Question : PostBase
{
public Question()
{
tags = new List<string>();
}
public string Title { get; set; }
public List<string> Tags { get { return tags; } }
public int NumberOfReplies { get; set; }
}
Answer:
public class Answer : PostBase
{
public string QuestionID { get; set; }
}
I use automapper to map to / from Answer and Post or Question and Post
What I'm trying to do, is create the following class:
public class QuestionWithAnswers
{
public Question Question { get; set; }
public IEnumerable<Answer> Answers { get; set; }
}
Which basically has a "Question" - remember this is just a Post in the db, with a ParentPostID of 0, with a list of Answers (where ParentPostID is equal to Question.ID ... or along those lines)
My question is - how do I map this in fluent nHibernate?

Answer 1

You could use Automapper for QuestionWithAnswers, but Answers has to have an IList and not an IEnumerable:
public class QuestionWithAnswers
{
public virtual Question Question { get; set; }
public virtual IList<Answer> Answers { get; set; }
}
What I don't understand is the existence of QuestionWithAnswers, when the following (I think) should do:
public class Question : PostBase
{
public virtual string Title { get; set; }
public virtual List<string> Tags { get { return tags; } }
public virtual int NumberOfReplies { get; set; }
public virtual IList<Answer> Answers { get; set; }
}
If the question has answers, you'll get them, and if it does not, you don't.