Question

[ Using Code First DbContext with Entity Framework 5.0 RC ]

Not sure what is happening?

• the individual Tracks are stored
• and the individual PlaybackEvents are stored
• but the ICollection<PlaybackEvent> of Track is not populated when I do var tracks = myDbContext.Tracks.ToList();
• even though I saved with myDbContext.Tracks.Add(track); myDbContext.SaveChanges(); where track had a couple of PlaybackEvents in ICollection<PlaybackEvents>

Hopefully Relevant Parts of Track

public class Track 
{
    public string Id {get; set;}

    private ICollection<PlaybackEvent> _playbackEvents;

    public ICollection<PlaybackEvent> PlaybackEvents
    {
        get { return _playbackEvents ?? (_playbackEvents = new List<PlaybackEvent>()); }
        set { _playbackEvents = value; }
    }
}

Simplified PlaybackEvent

public class PlaybackEvent {
    public string Id {get; set;}

    public string Track_Id { get; set; }
}

Answer 1

Your ICollection, which is your navigation property needs to be declared as virtual.

An additional suggestion to your code would be not to explicitly declare your getters and setters for your navigation property, but to move the setter responsibility to the constructor. Making your code look like this:

public class Track  
{ 
    public Track()
    {
        this.PlaybackEvents = new HashSet<PlaybackEvent>();
    }

    // Primary key
    public string Id {get; set;} 

    // Navigation property
    public virtual ICollection<PlaybackEvent> PlaybackEvents { get; private set; } 
 }

Your PlaybackEvent entity also needs a navigation property to enable the one Track to many PlaybackEvents relationship:

public class PlaybackEvent 
{  
    // Primary key
    public string Id {get; set;}  

    // Foreign key
    public string Track_Id { get; set; }  

    // Navigation property
    public virtual Track Track { get; set; }
}