Opc.Ua.Server.DataChangeMonitoredItem.QueueValue C# (CSharp) Method

        public void QueueValue(DataValue value, ServiceResult error)
        {
            lock (m_lock)
            {
                // check if value has changed.
                if (!m_alwaysReportUpdates)
                {
                    if (!Opc.Ua.Server.MonitoredItem.ValueChanged(value, error, m_lastValue, m_lastError, m_filter, m_range))
                    {
                        return;
                    }
                }

                // make a shallow copy of the value.
                if (value != null)
                {
                    DataValue copy = new DataValue();

                    copy.WrappedValue = value.WrappedValue;
                    copy.StatusCode = value.StatusCode;
                    copy.SourceTimestamp = value.SourceTimestamp;
                    copy.SourcePicoseconds = value.SourcePicoseconds;
                    copy.ServerTimestamp = value.ServerTimestamp;
                    copy.ServerPicoseconds = value.ServerPicoseconds;
                    
                    value = copy;

                    // ensure the data value matches the error status code.
                    if (error != null && error.StatusCode.Code != 0)
                    {
                        value.StatusCode = error.StatusCode;
                    }
                }

                m_lastValue = value;
                m_lastError = error;

                // queue value.
                if (m_queue != null)
                {
                    m_queue.QueueValue(value, error);
                }

                // flag the item as ready to publish.
                m_readyToPublish = true;
                m_readyToTrigger = true;
            }
        }

        /// <summary>
        /// Handles change events raised by the node.
        /// </summary>
        /// <param name="context">The system context.</param>
        /// <param name="state">The node that raised the event.</param>
        /// <param name="masks">What caused the event to be raised</param>
        public void OnNodeChange(ISystemContext context, NodeState state, NodeStateChangeMasks masks)
        {
            if (m_monitoredItems != null)
            {
                for (int ii = 0; ii < m_monitoredItems.Count; ii++)
                {
                    DataChangeMonitoredItem monitoredItem = m_monitoredItems[ii];

                    // check if the node has been deleted.
                    if ((masks & NodeStateChangeMasks.Deleted) != 0)
                    {
                        monitoredItem.QueueValue(null, StatusCodes.BadNodeIdUnknown);
                        continue;
                    }

                    if (monitoredItem.AttributeId == Attributes.Value)
                    {
                        if ((masks & NodeStateChangeMasks.Value) != 0)
                        {
                            monitoredItem.ValueChanged(context);
                        }
                    }
                    else
                    {
                        if ((masks & NodeStateChangeMasks.NonValue) != 0)
                        {
                            monitoredItem.ValueChanged(context);
                        }
                    }
                }
            }
        }