public class PersistentObject: SuperObject, IXPObject, IComparable {

Public Class PersistentObject
    Inherits SuperObject
    Implements IXPObject
    Implements IComparable

public PersistentObject(Session session) {
        this.session = session;
        this.classInfo = session.Dictionary.GetClassInfo(this.GetType());
        if(!session.IsObjectsLoading)
            AfterConstruction();
    }

    // Implement additional construction logic here
    protected void AfterConstruction() {
        if (Session is UnitOfWork && ClassInfo.IsPersistent) {
            Session.Save(this);
        }
    }

Public Sub New(ByVal session As Session)
        Me._session = session
        Me._classInfo = session.Dictionary.GetClassInfo(Me.GetType())
        If Not Me._session.IsObjectsLoading Then
            AfterConstruction()
        End If
    End Sub

    ' Implement additional construction logic here
    Protected Sub AfterConstruction()
        If TypeOf Session Is UnitOfWork AndAlso ClassInfo.IsPersistent Then
            Session.Save(Me)
        End If
    End Sub

int persistentID;
    [Key(AutoGenerate = true)]
    public int Oid {
        get { return persistentID; }
        set { 
            persistentID = value;
            OnChanged(nameof(Oid));
        }
    }

Dim persistentID As Integer
    <Key(AutoGenerate:=True)> _
    Public Property Oid() As Integer
        Get
            Return persistentID
        End Get
        Set(ByVal Value As Integer)
            persistentID = Value
            OnChanged(NameOf(Oid))
        End Set
    End Property

Session session;
    XPClassInfo classInfo;
    public Session Session { get { return this.session; } }
    public XPClassInfo ClassInfo { get { return this.classInfo; } }
    bool changed = false;

    public IDataLayer DataLayer { get { return session.DataLayer;} }
    public XPDictionary Dictionary { get { return session.Dictionary; } }

    protected void RaiseChangeEvent(ObjectChangeEventArgs args) {
        if(Changed != null)
            Changed(this, args);
    }
    public void OnChanged() {
        changed = true;
        if(!IsLoading)
            RaiseChangeEvent(new ObjectChangeEventArgs(Session, this, ObjectChangeReason.Reset));
    }
    protected void OnChanged(string propertyName) {
        changed = true;
        if(!IsLoading)
            RaiseChangeEvent(new ObjectChangeEventArgs(Session, this, ObjectChangeReason.PropertyChanged, propertyName, oldValue, newValue));
    }
    public event ObjectChangeEventHandler Changed;

    // The following three methods implement general persistent operations
    public void Save() {
        Session.Save(this);
    }
    public void Delete() {
        changed = true;
        Session.Delete(this);
        RaiseChangeEvent(new ObjectChangeEventArgs(Session, this, ObjectChangeReason.Delete));
    }
    public void Reload() {
        Session.Reload(this);
        collections.Clear(); // Required for collection properties (see implementation below)
        RaiseChangeEvent(new ObjectChangeEventArgs(Session, this, ObjectChangeReason.Reset));
    }

Dim _session As Session
    Dim _classInfo As XPClassInfo
    Public ReadOnly Property Session() As Session Implements IXPSimpleObject.Session
        Get
            Return Me._session
        End Get
    End Property
    Public ReadOnly Property ClassInfo() As XPClassInfo Implements IXPSimpleObject.ClassInfo
        Get
            Return Me._classInfo
        End Get
    End Property
    Dim _changed As Boolean = False

    Public ReadOnly Property DataLayer() As IDataLayer
        Get
            Return Me._session.DataLayer
        End Get
    End Property
    Public ReadOnly Property Dictionary() As XPDictionary
        Get
            Return Me._session.Dictionary
        End Get
    End Property

    Protected Sub RaiseChangeEvent(ByVal args As ObjectChangeEventArgs)
        RaiseEvent Changed(Me, args)
    End Sub
    Public Sub OnChanged()
        _changed = True
        If Not IsLoading Then
            RaiseChangeEvent(New ObjectChangeEventArgs(Session, Me, ObjectChangeReason.Reset))
        End If
    End Sub
    Protected Sub OnChanged(ByVal propertyName As String)
        _changed = True
        If Not IsLoading Then
            RaiseChangeEvent(New ObjectChangeEventArgs(Session, Me, ObjectChangeReason.PropertyChanged, propertyName, oldValue, newValue))
        End If
    End Sub
    Public Event Changed As ObjectChangeEventHandler Implements IXPSimpleObject.Changed

    ' The following three methods implement general persistent operations
    Public Sub Save()
        Session.Save(Me)
    End Sub
    Public Sub Delete()
        _changed = True
        Session.Delete(Me)
        RaiseChangeEvent(New ObjectChangeEventArgs(Session, Me, ObjectChangeReason.Delete))
    End Sub
    Public Sub Reload()
        Session.Reload(Me)
        _collections.Clear() ' Required for collection properties (see implementation below)
        RaiseChangeEvent(New ObjectChangeEventArgs(Session, Me, ObjectChangeReason.Reset))
    End Sub

int IComparable.CompareTo(object value) {
        return Comparer.Default.Compare(Session.GetKeyValue(this), 
          Session.GetKeyValue(value as IXPSimpleObject));
    }

Public Overridable Overloads Function CompareTo(ByVal value As Object) As Integer _
    Implements IComparable.CompareTo
        Return Comparer.Default.Compare(Session.GetKeyValue(Me), 
          Session.GetKeyValue(CType(value, IXPSimpleObject)))
    End Function

bool isLoading;
    [NonPersistent]
    public bool IsLoading { get { return isLoading; } }
    // Implement additional logic after an object has been deleted
    void IXPObject.OnDeleted() { }
    // Implement additional logic when an object is about to be deleted
    void IXPObject.OnDeleting() { }
    // Implement additional logic after an object has been loaded
    void IXPObject.OnLoaded() {
        isLoading = false;
    }
    // Implement additional logic before loading an object
    void IXPObject.OnLoading() {
        isLoading = true;
    }
    // Implement additional logic after an object has been saved
    void IXPObject.OnSaved() { }
    // Implement additional logic before saving an object
    void IXPObject.OnSaving() { }

Dim _isLoading As Boolean
    <NonPersistent()> _
    Public ReadOnly Property IsLoading() As Boolean
        Get
            Return _isLoading
        End Get
    End Property
    ' Implement additional logic after an object has been deleted
    Sub OnDeleted() Implements IXPObject.OnDeleted
    End Sub
    ' Implement additional logic when an object is about to be deleted
    Sub OnDeleting() Implements IXPObject.OnDeleting
    End Sub
    ' Implement additional logic after an object has been loaded
    Sub OnLoaded() Implements IXPObject.OnLoaded
        _isLoading = False
    End Sub
    ' Implement additional logic before loading an object
    Sub OnLoading() Implements IXPObject.OnLoading
        _isLoading = True
    End Sub
    ' Implement additional logic after an object has been saved
    Sub OnSaved() Implements IXPObject.OnSaved
    End Sub
    ' Implement additional logic before saving an object
    Sub OnSaving() Implements IXPObject.OnSaving
    End Sub

public object This { get { return this; } }

Public ReadOnly Property This() As Object
        Get
            Return Me
        End Get
    End Property

IDictionary collections;
    IDictionary Collections {
        get {
            if(collections == null)
                collections = new System.Collections.Specialized.HybridDictionary();
            return collections;
        }
    }
    XPMemberInfo GetCollectionProperty(string name) {
        XPMemberInfo p = ClassInfo.GetMember(name);
        if (p != null)
            return p;
        throw new PropertyMissingException(ClassInfo.FullName, name);
    }
    // Retrieves a collection by the name of the property which exposes the collection
    protected XPCollection GetCollection(string propertyName) {
        XPCollection result = Collections[propertyName] as XPCollection;
        if(result == null) {
            result = new XPCollection(this.Session, this, GetCollectionProperty(propertyName));
            Collections.Add(propertyName, result);
        }
        return result;
    }
}

Dim _collections As IDictionary
    ReadOnly Property Collections() As IDictionary
        Get
            If _collections Is Nothing Then
                _collections = New System.Collections.Specialized.HybridDictionary()
            End If
            Return _collections
        End Get
    End Property
    Function GetCollectionProperty(ByVal name As String) As XPMemberInfo
        Dim p As XPMemberInfo = ClassInfo.GetMember(name)
        If Not p Is Nothing Then
            Return p
        End If
        Throw New PropertyMissingException(ClassInfo.FullName, name)
    End Function
    ' Retrieves a collection by the name of the property which exposes the collection
    Protected Function GetCollection(ByVal propertyName As String) As XPCollection
        Dim result As XPCollection = CType(Collections.Item(propertyName), XPCollection)
        If result Is Nothing Then
            result = New XPCollection(Me.Session, Me, GetCollectionProperty(propertyName))
            Collections.Add(propertyName, result)
        End If
        Return result
    End Function
End Class

IObjectLayer IObjectLayerProvider.ObjectLayer {
        get { return Session.ObjectLayer; }
    }

Private ReadOnly Property ObjectLayer() As IObjectLayer Implements IObjectLayerProvider.ObjectLayer
        Get
            Return Session.ObjectLayer
        End Get
    End Property