/// <summary> /// Adds the monitored item to the collection. /// </summary> /// <param name="source">The source.</param> /// <param name="monitoredItem">The monitored item.</param> private HdaSubscribeAttributeRequest Add(NodeState source, MonitoredItem monitoredItem) { lock (m_lock) { m_monitoredItems.Add(monitoredItem.Id, monitoredItem); // get the HDA item id. string itemId = GetItemId(source); // create/update the subscribe request for the HDA item. if (itemId != null) { HdaSubscribeAttributeRequest request = FindAttributeRequest(itemId, true); if (request != null) { request.Add(m_context, monitoredItem); return(request); } } return(null); } }