Opc.Ua.Client.Session.ReadNode C# (CSharp) Method

ReadNode() private method

private ReadNode ( NodeId nodeId ) : Node
nodeId NodeId
return Node
        public Node ReadNode(NodeId nodeId)
        {
            // build list of attributes.
            SortedDictionary<uint,DataValue> attributes = new SortedDictionary<uint,DataValue>();
            
            attributes.Add(Attributes.NodeId, null);
            attributes.Add(Attributes.NodeClass, null);
            attributes.Add(Attributes.BrowseName, null);
            attributes.Add(Attributes.DisplayName, null);
            attributes.Add(Attributes.Description, null);
            attributes.Add(Attributes.WriteMask, null);
            attributes.Add(Attributes.UserWriteMask, null);
            attributes.Add(Attributes.DataType, null);
            attributes.Add(Attributes.ValueRank, null);
            attributes.Add(Attributes.ArrayDimensions, null);
            attributes.Add(Attributes.AccessLevel, null);
            attributes.Add(Attributes.UserAccessLevel, null);
            attributes.Add(Attributes.Historizing, null);
            attributes.Add(Attributes.MinimumSamplingInterval, null);
            attributes.Add(Attributes.EventNotifier, null);
            attributes.Add(Attributes.Executable, null);
            attributes.Add(Attributes.UserExecutable, null);
            attributes.Add(Attributes.IsAbstract, null);
            attributes.Add(Attributes.InverseName, null);
            attributes.Add(Attributes.Symmetric, null);
            attributes.Add(Attributes.ContainsNoLoops, null);

            // build list of values to read.
            ReadValueIdCollection itemsToRead = new ReadValueIdCollection();

            foreach (uint attributeId in attributes.Keys)
            {
                ReadValueId itemToRead = new ReadValueId();

                itemToRead.NodeId      = nodeId;
                itemToRead.AttributeId = attributeId;
                
                itemsToRead.Add(itemToRead);
            }

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

            ResponseHeader responseHeader = Read(
                null,
                0,
                TimestampsToReturn.Neither,
                itemsToRead,
                out values, 
                out diagnosticInfos);
            
            ClientBase.ValidateResponse(values, itemsToRead);
            ClientBase.ValidateDiagnosticInfos(diagnosticInfos, itemsToRead);

            // process results.
            int? nodeClass = null;

            for (int ii = 0; ii < itemsToRead.Count; ii++)
            {
                uint attributeId = itemsToRead[ii].AttributeId;
                
                // the node probably does not exist if the node class is not found.
                if (attributeId == Attributes.NodeClass)
                {
                    if (!DataValue.IsGood(values[ii]))
                    {
                        throw ServiceResultException.Create(values[ii].StatusCode, ii, diagnosticInfos, responseHeader.StringTable);
                    }       
     
                    // check for valid node class.
                    nodeClass  = values[ii].Value as int?;

                    if (nodeClass == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Node does not have a valid value for NodeClass: {0}.", values[ii].Value);
                    }
                }
                else
                {
                    if (!DataValue.IsGood(values[ii]))
                    {
                        // check for unsupported attributes.
                        if (values[ii].StatusCode == StatusCodes.BadAttributeIdInvalid)
                        {
                            continue;
                        }

                        // all supported attributes must be readable.
                        if (attributeId != Attributes.Value)
                        {
                            throw ServiceResultException.Create(values[ii].StatusCode, ii, diagnosticInfos, responseHeader.StringTable);
                        }
                    }      
                }

                attributes[attributeId] = values[ii];
            }

            Node node = null;
            DataValue value = null;

            switch ((NodeClass)nodeClass.Value)
            {
                default:
                {
                    throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Node does not have a valid value for NodeClass: {0}.", nodeClass.Value);
                }

                case NodeClass.Object:
                {
                    ObjectNode objectNode = new ObjectNode();

                    value = attributes[Attributes.EventNotifier];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Object does not support the EventNotifier attribute.");
                    }

                    objectNode.EventNotifier = (byte)attributes[Attributes.EventNotifier].GetValue(typeof(byte));
                    node = objectNode;
                    break;
                }

                case NodeClass.ObjectType:
                {
                    ObjectTypeNode objectTypeNode = new ObjectTypeNode();

                    value = attributes[Attributes.IsAbstract];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "ObjectType does not support the IsAbstract attribute.");
                    }

                    objectTypeNode.IsAbstract = (bool)attributes[Attributes.IsAbstract].GetValue(typeof(bool));
                    node = objectTypeNode;
                    break;
                }

                case NodeClass.Variable:
                {
                    VariableNode variableNode = new VariableNode();
                    
                    // DataType Attribute
                    value = attributes[Attributes.DataType];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Variable does not support the DataType attribute.");
                    }

                    variableNode.DataType = (NodeId)attributes[Attributes.DataType].GetValue(typeof(NodeId));     

                    // ValueRank Attribute
                    value = attributes[Attributes.ValueRank];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Variable does not support the ValueRank attribute.");
                    }

                    variableNode.ValueRank = (int)attributes[Attributes.ValueRank].GetValue(typeof(int));                                      
                    
                    // ArrayDimensions Attribute
                    value = attributes[Attributes.ArrayDimensions];

                    if (value != null)
                    {
                        if (value.Value == null)
                        {
                            variableNode.ArrayDimensions = new uint[0];
                        }
                        else
                        {
                            variableNode.ArrayDimensions = (uint[])value.GetValue(typeof(uint[]));
                        }
                    }
                    
                    // AccessLevel Attribute
                    value = attributes[Attributes.AccessLevel];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Variable does not support the AccessLevel attribute.");
                    }

                    variableNode.AccessLevel = (byte)attributes[Attributes.AccessLevel].GetValue(typeof(byte));     
                    
                    // UserAccessLevel Attribute
                    value = attributes[Attributes.UserAccessLevel];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Variable does not support the UserAccessLevel attribute.");
                    }

                    variableNode.UserAccessLevel = (byte)attributes[Attributes.UserAccessLevel].GetValue(typeof(byte));     
                    
                    // Historizing Attribute
                    value = attributes[Attributes.Historizing];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Variable does not support the Historizing attribute.");
                    }

                    variableNode.Historizing = (bool)attributes[Attributes.Historizing].GetValue(typeof(bool));    
                    
                    // MinimumSamplingInterval Attribute
                    value = attributes[Attributes.MinimumSamplingInterval];

                    if (value != null)
                    {
                        variableNode.MinimumSamplingInterval = Convert.ToDouble(attributes[Attributes.MinimumSamplingInterval].Value);
                    }

                    node = variableNode;
                    break;
                }
                    
                case NodeClass.VariableType:
                {
                    VariableTypeNode variableTypeNode = new VariableTypeNode();

                    // IsAbstract Attribute
                    value = attributes[Attributes.IsAbstract];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "VariableType does not support the IsAbstract attribute.");
                    }

                    variableTypeNode.IsAbstract = (bool)attributes[Attributes.IsAbstract].GetValue(typeof(bool));
                    
                    // DataType Attribute
                    value = attributes[Attributes.DataType];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "VariableType does not support the DataType attribute.");
                    }

                    variableTypeNode.DataType = (NodeId)attributes[Attributes.DataType].GetValue(typeof(NodeId));     

                    // ValueRank Attribute
                    value = attributes[Attributes.ValueRank];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "VariableType does not support the ValueRank attribute.");
                    }

                    variableTypeNode.ValueRank = (int)attributes[Attributes.ValueRank].GetValue(typeof(int));                                      
                    
                    // ArrayDimensions Attribute
                    value = attributes[Attributes.ArrayDimensions];

                    if (value != null && value.Value != null)
                    {
                        variableTypeNode.ArrayDimensions = (uint[])attributes[Attributes.ArrayDimensions].GetValue(typeof(uint[]));
                    }
                    
                    node = variableTypeNode;
                    break;
                }
                    
                case NodeClass.Method:
                {
                    MethodNode methodNode = new MethodNode();

                    // Executable Attribute
                    value = attributes[Attributes.Executable];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Method does not support the Executable attribute.");
                    }

                    methodNode.Executable = (bool)attributes[Attributes.Executable].GetValue(typeof(bool));
                    
                    // UserExecutable Attribute
                    value = attributes[Attributes.UserExecutable];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Method does not support the UserExecutable attribute.");
                    }

                    methodNode.UserExecutable = (bool)attributes[Attributes.UserExecutable].GetValue(typeof(bool));

                    node = methodNode;
                    break;
                }
                    
                case NodeClass.DataType:
                {
                    DataTypeNode dataTypeNode = new DataTypeNode();

                    // IsAbstract Attribute
                    value = attributes[Attributes.IsAbstract];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "DataType does not support the IsAbstract attribute.");
                    }

                    dataTypeNode.IsAbstract = (bool)attributes[Attributes.IsAbstract].GetValue(typeof(bool));

                    node = dataTypeNode;
                    break;
                }
                    
                case NodeClass.ReferenceType:
                {
                    ReferenceTypeNode referenceTypeNode = new ReferenceTypeNode();

                    // IsAbstract Attribute
                    value = attributes[Attributes.IsAbstract];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "ReferenceType does not support the IsAbstract attribute.");
                    }

                    referenceTypeNode.IsAbstract = (bool)attributes[Attributes.IsAbstract].GetValue(typeof(bool));

                    // Symmetric Attribute
                    value = attributes[Attributes.Symmetric];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "ReferenceType does not support the Symmetric attribute.");
                    }

                    referenceTypeNode.Symmetric = (bool)attributes[Attributes.IsAbstract].GetValue(typeof(bool));

                    // InverseName Attribute
                    value = attributes[Attributes.InverseName];

                    if (value != null && value.Value != null)
                    {
                        referenceTypeNode.InverseName = (LocalizedText)attributes[Attributes.InverseName].GetValue(typeof(LocalizedText));
                    }
                    
                    node = referenceTypeNode;
                    break;
                }
                    
                case NodeClass.View:
                {
                    ViewNode viewNode = new ViewNode();

                    // EventNotifier Attribute
                    value = attributes[Attributes.EventNotifier];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "View does not support the EventNotifier attribute.");
                    }

                    viewNode.EventNotifier = (byte)attributes[Attributes.EventNotifier].GetValue(typeof(byte));
                    
                    // ContainsNoLoops Attribute
                    value = attributes[Attributes.ContainsNoLoops];

                    if (value == null)
                    {
                        throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "View does not support the ContainsNoLoops attribute.");
                    }

                    viewNode.ContainsNoLoops = (bool)attributes[Attributes.ContainsNoLoops].GetValue(typeof(bool));

                    node = viewNode;
                    break;
                }                    
            }
                
            // NodeId Attribute
            value = attributes[Attributes.NodeId];

            if (value == null)
            {
                throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Node does not support the NodeId attribute.");
            }

            node.NodeId = (NodeId)attributes[Attributes.NodeId].GetValue(typeof(NodeId));
            node.NodeClass = (NodeClass)nodeClass.Value;

            // BrowseName Attribute
            value = attributes[Attributes.BrowseName];

            if (value == null)
            {
                throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Node does not support the BrowseName attribute.");
            }

            node.BrowseName = (QualifiedName)attributes[Attributes.BrowseName].GetValue(typeof(QualifiedName));

            // DisplayName Attribute
            value = attributes[Attributes.DisplayName];

            if (value == null)
            {
                throw ServiceResultException.Create(StatusCodes.BadUnexpectedError, "Node does not support the DisplayName attribute.");
            }

            node.DisplayName = (LocalizedText)attributes[Attributes.DisplayName].GetValue(typeof(LocalizedText));
    
            // Description Attribute
            value = attributes[Attributes.Description];

            if (value != null && value.Value != null)
            {
                node.Description = (LocalizedText)attributes[Attributes.Description].GetValue(typeof(LocalizedText));
            }

            // WriteMask Attribute
            value = attributes[Attributes.WriteMask];

            if (value != null)
            {
                node.WriteMask = (uint)attributes[Attributes.WriteMask].GetValue(typeof(uint));
            }

            // UserWriteMask Attribute
            value = attributes[Attributes.UserWriteMask];

            if (value != null)
            {
                node.WriteMask = (uint)attributes[Attributes.UserWriteMask].GetValue(typeof(uint));
            }
                
            return node;
        }