Opc.Ua.Com.Client.ComHdaBrowserClient.FindBranch C# (CSharp) Method

        private BaseObjectState FindBranch(ISystemContext context, string parentId, string itemId, ushort namespaceIndex)
        {
            // remove the enumerator.
            if (m_enumerator != null)
            {
                m_enumerator.Dispose();
                m_enumerator = null;
            }

            // find item at current level.
            m_enumerator = CreateEnumerator(true);
            List<string> children = new List<string>();

            do
            {
                // fetch the next name.
                string name = m_enumerator.Next();

                // a null indicates the end of list.
                if (name == null)
                {
                    break;
                }

                // create the node.
                string targetId = GetBranchPosition(parentId, name);

                if (itemId == targetId)
                {
                    return new HdaBranchState(itemId, name, namespaceIndex);
                }

                children.Add(targetId);
            }
            while (true);

            // recursively search for item ids.
            for (int ii = 0; ii < children.Count; ii++)
            {
                if (!ChangeBrowsePosition(OPCHDA_BROWSEDIRECTION.OPCHDA_BROWSE_DIRECT, children[ii]))
                {
                    continue;
                }

                BaseObjectState node = FindBranch(context, children[ii], itemId, namespaceIndex);

                if (node != null)
                {
                    return node;
                }
            }

            m_completed = true;
            return null;
        }
        #endregion

        /// <summary>
        /// Verifies that the specified node exists.
        /// </summary>
        protected override NodeState ValidateNode(
            ServerSystemContext context,
            NodeHandle handle,
            IDictionary<NodeId, NodeState> cache)
        {
            // not valid if no root.
            if (handle == null)
            {
                return null;
            }

            // check if previously validated.
            if (handle.Validated)
            {
                return handle.Node;
            }

            NodeState target = null;

            // check if already in the cache.
            if (cache != null)
            {
                if (cache.TryGetValue(handle.NodeId, out target))
                {
                    // nulls mean a NodeId which was previously found to be invalid has been referenced again.
                    if (target == null)
                    {
                        return null;
                    }

                    handle.Node = target;
                    handle.Validated = true;
                    return handle.Node;
                }

                target = null;
            }

            try
            {
                // check if the node id has been parsed.
                HdaParsedNodeId parsedNodeId = handle.ParsedNodeId as HdaParsedNodeId;

                if (parsedNodeId == null)
                {
                    return null;
                }

                ComHdaClient client = (ComHdaClient)m_system.SelectClient(context, false);

                switch (parsedNodeId.RootType)
                {
                    case HdaModelUtils.HdaBranch:
                    {
                        ComHdaBrowserClient browser = new ComHdaBrowserClient(client, null);
                        target = browser.FindBranch(context, parsedNodeId.RootId, NamespaceIndex);
                        browser.Dispose();
                        break;
                    }

                    case HdaModelUtils.HdaItem:
                    {
                        HdaItem[] items = client.GetItems(parsedNodeId.RootId);

                        if (items[0].Error < 0)
                        {
                            return null;
                        }

                        try
                        {
                            string browseName = null;

                            if (!m_configuration.ItemIdParser.Parse(client, m_configuration, parsedNodeId.RootId, out browseName))
                            {
                                HdaAttributeValue[] attributes = client.ReadAttributeValues(items[0].ServerHandle, OpcRcw.Hda.Constants.OPCHDA_ITEMID);
                                browseName = attributes[0].Value as string;
                            }

                            target = new HdaItemState(items[0].ItemId, browseName, NamespaceIndex);
                        }
                        finally
                        {
                            client.ReleaseItemHandles(items);
                        }

                        break;
                    }

                    case HdaModelUtils.HdaItemAttribute:
                    {
                        bool[] results = client.ValidateItemIds(parsedNodeId.RootId);

                        if (!results[0])
                        {
                            return null;
                        }

                        target = client.FindItemAttribute(parsedNodeId.RootId, parsedNodeId.AttributeId, NamespaceIndex);
                        break;
                    }

                    case HdaModelUtils.HdaItemAnnotations:
                    {
                        bool[] results = client.ValidateItemIds(parsedNodeId.RootId);

                        if (!results[0])
                        {
                            return null;
                        }

                        target = client.FindItemAnnotations(parsedNodeId.RootId, NamespaceIndex);
                        break;
                    }

                    case HdaModelUtils.HdaItemConfiguration:
                    {
                        bool[] results = client.ValidateItemIds(parsedNodeId.RootId);

                        if (results == null || !results[0])
                        {
                            return null;
                        }

                        target = HdaModelUtils.GetItemConfigurationNode(parsedNodeId.RootId, NamespaceIndex);
                        target.OnCreateBrowser = OnCreateItemConfigurationBrowser;
                        break;
                    }

                    case HdaModelUtils.HdaAggregate:
                    {
                        target = client.FindAggregate(parsedNodeId.AggregateId, NamespaceIndex);
                        break;
                    }
                }

                // check if found.
                if (target == null)
                {
                    return null;
                }

                // found a valid component.
                handle.Validated = true;
                handle.Node = target;

                return handle.Node;
            }
            finally
            {
                // store the node in the cache to optimize subsequent lookups.
                if (cache != null)
                {
                    cache.Add(handle.NodeId, target);
                }
            }
        }