Public Overridable Property Tag As Integer

Dim instance As AnnObject
Dim value As Integer
 
instance.Tag = value
 
value = instance.Tag

public virtual int Tag {get; set;}

public:
virtual property int Tag {
   int get();
   void set (    int value);
}

Private tagCount As Integer
Public Sub AnnObject_Tag()
   tagCount = 0
   ' create a container and subclass to its Objects.ItemAdded event
   Dim container As AnnContainer = New AnnContainer()
   AddHandler container.Objects.ItemAdded, AddressOf AnObjectAddedToContainer

   ' add a few objects to the container
   Dim lineObj As AnnLineObject = New AnnLineObject()
   container.Objects.Add(lineObj)

   Dim rectObj As AnnRectangleObject = New AnnRectangleObject()
   container.Objects.Add(rectObj)

   Dim ellipseObj As AnnEllipseObject = New AnnEllipseObject()
   container.Objects.Add(ellipseObj)

   ' enumerate the objects in the container and show their tag
   For Each obj As AnnObject In container.Objects
      MessageBox.Show(String.Format("Object type: {0}, Tag: {1}", obj.GetType().Name, obj.Tag))
   Next obj
End Sub

Private Sub AnObjectAddedToContainer(ByVal sender As Object, ByVal e As RasterCollectionEventArgs(Of AnnObject))
   ' get the object
   Dim obj As AnnObject = e.Item

   ' update its tag
   obj.Tag = tagCount
   tagCount += 1
End Sub

private int tagCount;
public void AnnObject_Tag()
{
   tagCount = 0;
   // create a container and subclass to its Objects.ItemAdded event
   AnnContainer container = new AnnContainer();
   container.Objects.ItemAdded += new EventHandler<RasterCollectionEventArgs<AnnObject>>(AnObjectAddedToContainer);

   // add a few objects to the container
   AnnLineObject lineObj = new AnnLineObject();
   container.Objects.Add(lineObj);

   AnnRectangleObject rectObj = new AnnRectangleObject();
   container.Objects.Add(rectObj);

   AnnEllipseObject ellipseObj = new AnnEllipseObject();
   container.Objects.Add(ellipseObj);

   // enumerate the objects in the container and show their tag
   foreach(AnnObject obj in container.Objects)
      MessageBox.Show(String.Format("Object type: {0}, Tag: {1}", obj.GetType().Name, obj.Tag));
}

private void AnObjectAddedToContainer(object sender, RasterCollectionEventArgs<AnnObject> e)
{
   // get the object
   AnnObject obj = e.Item;

   // update its tag
   obj.Tag = tagCount;
   tagCount++;
}