Opc.Ua.Server.CustomNodeManager2.ModifyMonitoredItem C# (CSharp) Method

        protected virtual ServiceResult ModifyMonitoredItem(
            ServerSystemContext context,
            DiagnosticsMasks diagnosticsMasks,
            TimestampsToReturn timestampsToReturn,
            IMonitoredItem monitoredItem,
            MonitoredItemModifyRequest itemToModify,
            NodeHandle handle,
            out MonitoringFilterResult filterResult)
        {
            filterResult = null;
            
            // check for valid monitored item.
            MonitoredItem datachangeItem = monitoredItem as MonitoredItem;

            // validate parameters.
            MonitoringParameters parameters = itemToModify.RequestedParameters;

            double previousSamplingInterval = datachangeItem.SamplingInterval;
            
            // check if the variable needs to be sampled.
            double samplingInterval = itemToModify.RequestedParameters.SamplingInterval;

            if (samplingInterval < 0)
            {
                samplingInterval = previousSamplingInterval;
            }

            // ensure minimum sampling interval is not exceeded.
            if (datachangeItem.AttributeId == Attributes.Value)
            {
                BaseVariableState variable = handle.Node as BaseVariableState;

                if (variable != null && samplingInterval < variable.MinimumSamplingInterval)
                {
                    samplingInterval = variable.MinimumSamplingInterval;
                }
            }

            // put a large upper limit on sampling.
            if (samplingInterval == Double.MaxValue)
            {
                samplingInterval = 365 * 24 * 3600 * 1000.0;
            }

            // put an upper limit on queue size.
            uint queueSize = itemToModify.RequestedParameters.QueueSize;

            if (queueSize > m_maxQueueSize)
            {
                queueSize = m_maxQueueSize;
            }

            // validate the monitoring filter.
            Range euRange = null;
            MonitoringFilter filterToUse = null;

            ServiceResult error = ValidateMonitoringFilter(
                context,
                handle,
                datachangeItem.AttributeId,
                samplingInterval,
                queueSize,
                parameters.Filter,
                out filterToUse,
                out euRange,
                out filterResult);

            if (ServiceResult.IsBad(error))
            {
                return error;
            }

            // modify the monitored item parameters.
            error = datachangeItem.ModifyAttributes(
                diagnosticsMasks,
                timestampsToReturn,
                itemToModify.RequestedParameters.ClientHandle,
                filterToUse,
                filterToUse,
                euRange,
                samplingInterval,
                queueSize,
                itemToModify.RequestedParameters.DiscardOldest);
            
            // report change.
            if (ServiceResult.IsGood(error))
            {
                OnMonitoredItemModified(context, handle, datachangeItem);
            }

            return error;
        }