Opc.Ua.AttributeOperand.Validate C# (CSharp) Method

        public override ServiceResult Validate(FilterContext context, int index)
        {
            m_validated = false;

            // verify that the operand refers to a node in the type model.
            if (!context.TypeTree.IsKnown(m_nodeId))
            {                
                return ServiceResult.Create(
                    StatusCodes.BadTypeDefinitionInvalid, 
                    "AttributeOperand does not have a known TypeDefinitionId ({0}).", 
                    m_nodeId);
            }

            // verify attribute id.
            if (!Attributes.IsValid(m_attributeId))
            {
                return ServiceResult.Create(
                    StatusCodes.BadAttributeIdInvalid, 
                    "AttributeOperand does not specify a valid AttributeId ({0}).", 
                    m_attributeId);
            }

            // initialize as empty.
            m_parsedIndexRange = NumericRange.Empty;

            // parse the index range.
            if (!String.IsNullOrEmpty(m_indexRange))
            {
                try
                {
                    m_parsedIndexRange = NumericRange.Parse(m_indexRange);
                }
                catch (Exception e)
                {
                    return ServiceResult.Create(
                        e,
                        StatusCodes.BadIndexRangeInvalid, 
                        "AttributeOperand does not specify a valid BrowsePath ({0}).", 
                        m_indexRange);
                }

                if (m_attributeId != Attributes.Value)
                {
                    return ServiceResult.Create(
                        StatusCodes.BadIndexRangeInvalid, 
                        "AttributeOperand specifies an IndexRange for an Attribute other than Value ({0}).", 
                        m_attributeId);
                }
            }

            m_validated = true;

            return ServiceResult.Good;
        }