Question

I have a DB that was built with EF 4 code first, here’s two models:

Public Class HvacAudit
    Public Property HvacAuditID As Integer

    Public Overridable Property HvacAuditPictures As IEnumerable(Of HvacAuditPicture)

    ... other properties
 End Class

Public Class HvacAuditPicture
    Public Property HvacAuditPictureID As Integer

    Public Property HvacAuditID As Integer
    Public Overridable Property HvacAudit As HvacAudit

    ... other properties
End Class

When I pull my HvacAudit records from the db, they don’t have HvacAuditPictures! Even though if I pull the pictures directly, they are there. Consider

context.HvacAudits.Where(Function(hva) hva.HvacAuditID = 1).HvacAuditPictures Is Nothing 'evaluates true

context.HvacAuditPictures.Where(Function(p) p.HvacAuditID = 1).Count() 'is currently 20

Here’s my context class:

Public Class EfContext
Inherits DbContext
Implements IDataSource

Public Property HvacAudits As IDbSet(Of HvacAudit) Implements IDataSource.HvacAudits
Public Property Vendors As IDbSet(Of Vendor) Implements IDataSource.Vendors
Public Property HvacAuditPictures As IDbSet(Of HvacAuditPicture) Implements IDataSource.HvacAuditPictures
Public Property Sites As IDbSet(Of Site)
Public Property Markets As IDbSet(Of Market)

Public Sub SaveChanges1() Implements Domain.DataSource.IDataSource.SaveChanges
    SaveChanges()
End Sub
End Class

Answer 1

Found the answer. The navigation property for the “many” side of a relationship has to be an ICollection(Of T), not an IEnumerable(Of T).

Public Class HvacAudit
    Public Property HvacAuditID As Integer

    Public Overridable Property HvacAuditPictures As ICollection(Of HvacAuditPicture)

   ... other properties
End Class