Opc.Ua.Com.Server.ComHdaItemManager.ReadCurrentValues C# (CSharp) Method

        public DaValue[] ReadCurrentValues(Session session, HdaItemHandle itemHandle, uint[] attributeIds)
        {
            DaValue[] results = new DaValue[attributeIds.Length];

            // check handle.
            InternalHandle handle = itemHandle as InternalHandle;

            if (handle == null)
            {
                for (int ii = 0; ii < results.Length; ii++)
                {
                    results[ii] = new DaValue();
                    results[ii].Error = ResultIds.E_INVALIDHANDLE;
                }

                return results;
            }

            // look up the supported attributes for an item.
            ReadValueIdCollection supportedAttributes = handle.Item.SupportedAttributes;

            if (supportedAttributes == null)
            {
                handle.Item.SupportedAttributes = supportedAttributes = GetAvailableAttributes(session, handle.NodeId);
            }

            // build list of values to read.
            ReadValueIdCollection valuesToRead = new ReadValueIdCollection();
            List<int> indexes = new List<int>();

            for (int ii = 0; ii < attributeIds.Length; ii++)
            {
                ReadValueId valueToRead = GetReadValueId(supportedAttributes, attributeIds[ii]);

                if (valueToRead == null)
                {
                    results[ii] = new DaValue();
                    results[ii].Error = ResultIds.E_INVALIDATTRID;
                    continue;
                }

                valuesToRead.Add(valueToRead);
                indexes.Add(ii);

                // need to fetch the value rank as well.
                if (attributeIds[ii] == Constants.OPCHDA_DATA_TYPE)
                {
                    valuesToRead.Add(GetReadValueId(supportedAttributes, ComHdaProxy.INTERNAL_ATTRIBUTE_VALUE_RANK));
                    indexes.Add(-1);
                }
            }

            // nothing to do.
            if (valuesToRead.Count == 0)
            {
                return results;
            }

            // read values from the UA server.
            DataValueCollection values = null;
            DiagnosticInfoCollection diagnosticInfos = null;

            session.Read(
                null,
                0,
                TimestampsToReturn.Neither,
                valuesToRead,
                out values,
                out diagnosticInfos);

            // validate response from the UA server.
            ClientBase.ValidateResponse(values, valuesToRead);
            ClientBase.ValidateDiagnosticInfos(diagnosticInfos, valuesToRead);

            // assign a local handle to all valid items.
            for (int ii = 0; ii < valuesToRead.Count; ii++)
            {
                int index = indexes[ii];
                uint attributeId = (uint)valuesToRead[ii].Handle;

                // check for values which are combined with other values to create the value (e.g. ValueRank).
                if (index == -1)
                {
                    continue;
                }

                results[index] = GetAttributeValue(session, attributeId, values, ii);

                // only support current value for now.
                if (results[index].Error == ResultIds.S_OK)
                {
                    results[index].Error = ResultIds.S_CURRENTVALUE;
                }
            }

            return results;
        }