System.Xml.Serialization.XmlSchemaImporter.ImportChoiceGroup C# (CSharp) Method

        private MemberMapping ImportChoiceGroup(XmlSchemaGroupBase group, string identifier, CodeIdentifiers members, CodeIdentifiers membersScope, INameScope elementsScope, string ns, bool groupRepeats, ref bool needExplicitOrder, bool allowDuplicates)
        {
            NameTable choiceElements = new NameTable();
            if (GatherGroupChoices(group, choiceElements, identifier, ns, ref needExplicitOrder, allowDuplicates))
                groupRepeats = true;
            MemberMapping member = new MemberMapping();
            member.Elements = (ElementAccessor[])choiceElements.ToArray(typeof(ElementAccessor));
            Array.Sort(member.Elements, new ElementComparer());

            AddScopeElements(elementsScope, member.Elements, ref needExplicitOrder, allowDuplicates);
            bool duplicateTypes = false;
            bool nullableMismatch = false;
            Hashtable uniqueTypeDescs = new Hashtable(member.Elements.Length);

            for (int i = 0; i < member.Elements.Length; i++)
            {
                ElementAccessor element = member.Elements[i];
                string tdFullName = element.Mapping.TypeDesc.FullName;
                object val = uniqueTypeDescs[tdFullName];
                if (val != null)
                {
                    duplicateTypes = true;
                    ElementAccessor existingElement = (ElementAccessor)val;
                    if (!nullableMismatch && existingElement.IsNullable != element.IsNullable)
                        nullableMismatch = true;
                }
                else
                {
                    uniqueTypeDescs.Add(tdFullName, element);
                }

                ArrayMapping arrayMapping = element.Mapping as ArrayMapping;
                if (arrayMapping != null)
                {
                    if (IsNeedXmlSerializationAttributes(arrayMapping))
                    {
                        // we cannot use ArrayMapping in choice if additional custom 
                        // serialization attributes are needed to serialize it
                        element.Mapping = arrayMapping.TopLevelMapping;
                        element.Mapping.ReferencedByTopLevelElement = false;
                        element.Mapping.ReferencedByElement = true;
                    }
                }
            }
            if (nullableMismatch)
                member.TypeDesc = Scope.GetTypeDesc(typeof(object));
            else
            {
                TypeDesc[] typeDescs = new TypeDesc[uniqueTypeDescs.Count];
                IEnumerator enumerator = uniqueTypeDescs.Values.GetEnumerator();
                for (int i = 0; i < typeDescs.Length; i++)
                {
                    if (!enumerator.MoveNext())
                        break;
                    typeDescs[i] = ((ElementAccessor)enumerator.Current).Mapping.TypeDesc;
                }
                member.TypeDesc = TypeDesc.FindCommonBaseTypeDesc(typeDescs);
                if (member.TypeDesc == null) member.TypeDesc = Scope.GetTypeDesc(typeof(object));
            }

            if (groupRepeats)
                member.TypeDesc = member.TypeDesc.CreateArrayTypeDesc();

            if (membersScope != null)
            {
                member.Name = membersScope.AddUnique(groupRepeats ? "Items" : "Item", member);
                if (members != null)
                {
                    members.Add(member.Name, member);
                }
            }

            if (duplicateTypes)
            {
                member.ChoiceIdentifier = new ChoiceIdentifierAccessor();
                member.ChoiceIdentifier.MemberName = member.Name + "ElementName";
                // we need to create the EnumMapping to store all of the element names
                member.ChoiceIdentifier.Mapping = ImportEnumeratedChoice(member.Elements, ns, member.Name + "ChoiceType");
                member.ChoiceIdentifier.MemberIds = new string[member.Elements.Length];
                ConstantMapping[] constants = ((EnumMapping)member.ChoiceIdentifier.Mapping).Constants;
                for (int i = 0; i < member.Elements.Length; i++)
                {
                    member.ChoiceIdentifier.MemberIds[i] = constants[i].Name;
                }
                MemberMapping choiceIdentifier = new MemberMapping();
                choiceIdentifier.Ignore = true;
                choiceIdentifier.Name = member.ChoiceIdentifier.MemberName;
                if (groupRepeats)
                {
                    choiceIdentifier.TypeDesc = member.ChoiceIdentifier.Mapping.TypeDesc.CreateArrayTypeDesc();
                }
                else
                {
                    choiceIdentifier.TypeDesc = member.ChoiceIdentifier.Mapping.TypeDesc;
                }

                // create element accessor for the choiceIdentifier

                ElementAccessor choiceAccessor = new ElementAccessor();
                choiceAccessor.Name = choiceIdentifier.Name;
                choiceAccessor.Namespace = ns;
                choiceAccessor.Mapping = member.ChoiceIdentifier.Mapping;
                choiceIdentifier.Elements = new ElementAccessor[] { choiceAccessor };

                if (membersScope != null)
                {
                    choiceAccessor.Name = choiceIdentifier.Name = member.ChoiceIdentifier.MemberName = membersScope.AddUnique(member.ChoiceIdentifier.MemberName, choiceIdentifier);
                    if (members != null)
                    {
                        members.Add(choiceAccessor.Name, choiceIdentifier);
                    }
                }
            }
            return member;
        }