iTextSharp.text.pdf.PdfLayer.AddChild C# (CSharp) Метод

        public void AddChild(PdfLayer child)
        {
            if (child.parent != null)
                throw new ArgumentException(MessageLocalization.GetComposedMessage("the.layer.1.already.has.a.parent", child.GetAsString(PdfName.NAME).ToUnicodeString()));
            child.parent = this;
            if (children == null)
                children = new List<PdfLayer>();
            children.Add(child);
        }

 /**
 * Recursive method to reconstruct the documentOCGorder variable in the writer.
 * @param    parent  a parent PdfLayer (can be null)
 * @param    arr     an array possibly containing children for the parent PdfLayer
 * @param    ocgmap  a Hashtable with indirect reference Strings as keys and PdfLayer objects as values.
 * @since    2.1.2
 */
 private void AddOrder(PdfLayer parent, PdfArray arr, Dictionary<string,PdfLayer> ocgmap) {
     PdfObject obj;
     PdfLayer layer;
     for (int i = 0; i < arr.Size; i++) {
         obj = arr[i];
         if (obj.IsIndirect()) {
             layer = ocgmap[obj.ToString()];
             if (layer != null) {
                 layer.OnPanel = true;
                 RegisterLayer(layer);
                 if (parent != null) {
                     parent.AddChild(layer);
                 }
                 if (arr.Size > i + 1 && arr[i + 1].IsArray()) {
                     i++;
                     AddOrder(layer, (PdfArray)arr[i], ocgmap);
                 }
             }
         }
         else if (obj.IsArray()) {
             PdfArray sub = (PdfArray)obj;
             if (sub.IsEmpty()) return;
             obj = sub[0];
             if (obj.IsString()) {
                 layer = new PdfLayer(obj.ToString());
                 layer.OnPanel = true;
                 RegisterLayer(layer);
                 if (parent != null) {
                     parent.AddChild(layer);
                 }
                 PdfArray array = new PdfArray();
                 for (ListIterator<PdfObject> j = sub.GetListIterator(); j.HasNext(); ) {
                     array.Add(j.Next());
                 }
                 AddOrder(layer, array, ocgmap);
             }
             else {
                 AddOrder(parent, (PdfArray)obj, ocgmap);
             }
         }
     }
 }