public void Update()
        {
            M2SceneNode node = ModelSceneService.Instance.MainM2SceneNode;

            Attachments.Clear();

            if (node == null)
            {
                return;
            }

            int num = (int)node.FileM2.numAttachments;

            for (int i = 0; i < num; ++i)
            {
                M2Attachment a = new M2Attachment(i, node.IsAttachmentShow(i));
                Attachments.Add(a);

                a.PropertyChanged += new PropertyChangedEventHandler(attachment_PropertyChanged);
            }

            attachmentsView = CollectionViewSource.GetDefaultView(Attachments);
        }