Linq to SQL to ObservableCollection for treeview in VB.Net - vb.net

Question

I have some Linq to SQL table classes that are joined together. I currently have it bound to a treeview using just the LINQ to SQL query. It works, but it doesn't show when stuff is added or removed from the database.
I implemented INotifyPropertyChanged but it isn't updating the treeview.
I also tried using Bindable Linq, but it doesn't seem to make a difference.
I found an example of a way to easily create ObservableCollections without having to create more classes: jimlynn.wordpress.com/2008/12/09/using-observablecollection-with-linq/, (which is kind of important because I have a future project looming that will require interacting with a lot of tables (30 or so) and just creating the Linq to SQL classes is going to be a pain).
Property ModelQuery As ObservableCollection(Of dbModels) = New ObservableCollection(Of dbModels)().PopulateFrom(From mm In tblModels.AsBindable Order By mm.ModelName)
Is this a good way to go, or am I going to have to create a separate ObservableCollection and maintain them both in code. If I'm going to use this binding stuff, I'm really looking for a way to have stuff just linked together so I don't have to update multiple structures whenever a change is made.
Main table:
<Table(Name:="Models")> Public Class dbModels
Implements INotifyPropertyChanged
Private _changed As Boolean
Public Event PropertyChanged(ByVal sender As Object, ByVal e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged
Protected Overridable Sub OnPropertyChanged(ByVal Propertyname As String)
If Not Propertyname.Contains("Changed") Then
Changed = True
End If
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(Propertyname))
End Sub
Public Property Changed() As Boolean
Get
Return _changed
End Get
Set(ByVal value As Boolean)
If _changed <> value Then
_changed = value
OnPropertyChanged("Changed")
End If
End Set
End Property
Private _ModelID As Integer
<Column(Storage:="_ModelID", DbType:="int IDENTITY NOT NULL", IsPrimaryKey:=True, IsDbGenerated:=True, Name:="ModelID")> _
Public Property ModelID() As Integer
Get
Return Me._ModelID
End Get
Set(value As Integer)
Me._ModelID = value
End Set
End Property
Private _ModelName As String
<Column(Storage:="_ModelName", DbType:="Varchar(200)", Name:="ModelName")> _
Public Property ModelName() As String
Get
Return Me._ModelName
End Get
Set(value As String)
Me._ModelName = value
End Set
End Property
Private _ModelYears As EntitySet(Of dbModelYears) = New EntitySet(Of dbModelYears)
<Association(Storage:="_ModelYears", DeleteRule:="CASCADE", OtherKey:="ModelID")> _
Public Property ModelYears As EntitySet(Of dbModelYears)
Get
Return _ModelYears
End Get
Set(value As EntitySet(Of dbModelYears))
_ModelYears.Assign(value)
End Set
End Property
End Class
Joined table:
<Table(Name:="ModelYears")> Public Class dbModelYears
Implements INotifyPropertyChanged
Private _changed As Boolean
Public Event PropertyChanged(ByVal sender As Object, ByVal e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged
Protected Overridable Sub OnPropertyChanged(ByVal Propertyname As String)
If Not Propertyname.Contains("Changed") Then
Changed = True
End If
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(Propertyname))
End Sub
Public Property Changed() As Boolean
Get
Return _changed
End Get
Set(ByVal value As Boolean)
If _changed <> value Then
_changed = value
OnPropertyChanged("Changed")
End If
End Set
End Property
Private _ModelYearID As Integer
<Column(Storage:="_ModelYearID", DbType:="int IDENTITY NOT NULL", IsPrimaryKey:=True, IsDbGenerated:=True, Name:="ModelYearID")> _
Public Property ModelYearID() As Integer
Get
Return Me._ModelYearID
End Get
Set(value As Integer)
Me._ModelYearID = value
End Set
End Property
Private _ModelID As Integer
<Column(Storage:="_ModelID", DbType:="int", Name:="ModelID")> _
Public Property ModelID() As Integer
Get
Return Me._ModelID
End Get
Set(value As Integer)
Me._ModelID = value
End Set
End Property
Private _ModelYear As String
<Column(Storage:="_ModelYear", DbType:="Varchar(50)", Name:="ModelYear")> _
Public Property ModelYear() As String
Get
Return Me._ModelYear
End Get
Set(value As String)
Me._ModelYear = value
End Set
End Property
End Class

Answer 1

Implementing INotifyPropertyChanged or using ObservableCollection wont notify you of changes in the database. You are going to have to execute the query every time you want to retrieve new data from the database.
Alternatively you could possibly use SqlDependency to set up a query notification dependency between your application and an instance of SQL Server.
EDIT:
From comments.
To hook up the PropertyChanged event of the items in the collection.
For Each item As var In itemsCollection
Dim notifyItem = TryCast(item, INotifyPropertyChanged)
If item IsNot Nothing Then
AddHandler notifyItem.PropertyChanged, AddressOf ItemChanged
End If
Next
Public Sub ItemChanged(sender As Object, e As PropertyChangedEventArgs)
'Handle event
End Sub