Question

Sorry for the bad title, I really don’t know how to word it better.

I have a SQL table named Posts and a class named Post. A post can be multiple things such as a Thread or a ThreadReply, which are subclasses of Post but are all stored in the same Post table. To identify the type of Post it has a PostType field.

[Table(Name = "Posts")]
public class Post
{
    [Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
    public int Id { get; set; }

    [Column]
    public PostType Type { get; set; }

    // ...
 }

 public class Thread : Post { /* ... */ };
 public class ThreadReply : Post { /* ... */ };

I use this to get the posts from the database in my IPostsRepository:

 db.GetTable<Post>(); // IQueryable<Post>

However they are all instantiated as Post (obviously). I want them to be instantiated based on their PostType, so that things like Thread t = p as Thread; will work.

Any ideas?

Answer 1

Use IsDiscriminator attribute to define table per Class Hierarchy.