Opc.Ua.Com.Server.ComAe2Subscription.UpdateAreaFilter C# (CSharp) Method

        private void UpdateAreaFilter(List<NodeId> areas)
        {
            // check if monitoring all events.
            if (areas == null || areas.Count == 0)
            {
                MonitoredItem monitoredItem = null;

                if (!m_notifiers.TryGetValue(Opc.Ua.ObjectIds.Server, out monitoredItem))
                {
                    monitoredItem = CreateMonitoredItem(Opc.Ua.ObjectIds.Server);
                }

                m_notifiers.Clear();
                m_notifiers[Opc.Ua.ObjectIds.Server] = monitoredItem;
                return;
            }

            // build table of areas to monitor.
            NodeIdDictionary<MonitoredItem> notifiers = new NodeIdDictionary<MonitoredItem>();

            // map all of the area search strings onto NodeIds for notifiers.
            for (int ii = 0; ii < areas.Count; ii++)
            {
                NodeId areaId = areas[ii];

                // check for existing item.
                MonitoredItem monitoredItem = null;

                if (m_notifiers.TryGetValue(areaId, out monitoredItem))
                {
                    notifiers[areaId] = monitoredItem;
                    continue;
                }

                // check for new item.
                if (!notifiers.ContainsKey(areaId))
                {
                    notifiers[areaId] = CreateMonitoredItem(areaId);
                }
            }

            // mark unused items for deletion.
            foreach (MonitoredItem monitoredItem in m_notifiers.Values)
            {
                if (!notifiers.ContainsKey(monitoredItem.StartNodeId))
                {
                    m_subscription.RemoveItem(monitoredItem);
                }
            }

            m_notifiers = notifiers;
        }