jabber.connection.ItemList.this C# (CSharp) Method

        public XmlElement this[string id]
        {
            get
            {
                object index = m_index[id];
                if (index == null)
                    return null;
                PubSubItem item = this[(int)index] as PubSubItem;
                if (item == null)
                    return null;
                return item.Contents;
            }
            set
            {
                // wrap an item around the contents.
                PubSubItem item = new PubSubItem(value.OwnerDocument);
                item.Contents = value;
                item.ID = id;
                Add(item);
            }
        }