System.Xml.Serialization.XmlReflectionImporter.CheckAmbiguousChoice C# (CSharp) Method

        private void CheckAmbiguousChoice(XmlAttributes a, Type accessorType, string accessorName)
        {
            Hashtable choiceTypes = new Hashtable();

            XmlElementAttributes elements = a.XmlElements;
            if (elements != null && elements.Count >= 2 && a.XmlChoiceIdentifier == null)
            {
                for (int i = 0; i < elements.Count; i++)
                {
                    Type type = elements[i].Type == null ? accessorType : elements[i].Type;
                    if (choiceTypes.Contains(type))
                    {
                        // You need to add {0} to the '{1}'.
                        throw new InvalidOperationException(SR.Format(SR.XmlChoiceIdentiferMissing, typeof(XmlChoiceIdentifierAttribute).Name, accessorName));
                    }
                    else
                    {
                        choiceTypes.Add(type, false);
                    }
                }
            }
            if (choiceTypes.Contains(typeof(XmlElement)) && a.XmlAnyElements.Count > 0)
            {
                // You need to add {0} to the '{1}'.
                throw new InvalidOperationException(SR.Format(SR.XmlChoiceIdentiferMissing, typeof(XmlChoiceIdentifierAttribute).Name, accessorName));
            }

            XmlArrayItemAttributes items = a.XmlArrayItems;
            if (items != null && items.Count >= 2)
            {
                NameTable arrayTypes = new NameTable();

                for (int i = 0; i < items.Count; i++)
                {
                    Type type = items[i].Type == null ? accessorType : items[i].Type;
                    string ns = items[i].NestingLevel.ToString(CultureInfo.InvariantCulture);
                    XmlArrayItemAttribute item = (XmlArrayItemAttribute)arrayTypes[type.FullName, ns];
                    if (item != null)
                    {
                        throw new InvalidOperationException(SR.Format(SR.XmlArrayItemAmbiguousTypes, accessorName, item.ElementName, items[i].ElementName, typeof(XmlElementAttribute).Name, typeof(XmlChoiceIdentifierAttribute).Name, accessorName));
                    }
                    else
                    {
                        arrayTypes[type.FullName, ns] = items[i];
                    }
                }
            }
        }