private void TraverseParticle(XmlSchemaParticle particle, XmlSchemaComplexType baseType, ClrContentTypeInfo typeInfo, XmlSchemaDerivationMethod derivationMethod)
        {
            if (particleStack == null)
            {
                particleStack = new Stack<ParticleData>();
            }
            else
            {
                particleStack.Clear();
            }
            if (propertyNameTypeTable == null)
            {
                propertyNameTypeTable = new Dictionary<string, ClrPropertyInfo>();
            }
            else
            {
                propertyNameTypeTable.Clear();
            }

            XmlSchemaParticle baseParticle = baseType.ContentTypeParticle;
            ParticleData particleData;
            GroupingInfo parentGroupInfo = null;
            StringBuilder regEx = new StringBuilder();

            XmlSchemaGroupBase currentGroupBase = null;
            GroupingInfo currentGroupingInfo = null;

            int currentIndex = 0;

            while (true)
            {

                // dont interrogate a particle if we are past the end of the list
                if (currentGroupBase == null || currentIndex <= currentGroupBase.Items.Count)
                {
                    ParticleType particleType = particle.GetParticleType();
                    switch (particleType)
                    {
                        case ParticleType.Element:
                            {
                                XmlSchemaElement elem = particle as XmlSchemaElement;
                                ClrPropertyInfo propertyInfo = null;
                                bool fromBaseType = false;
                                if (derivationMethod == XmlSchemaDerivationMethod.Extension && typeInfo.IsDerived)
                                {
                                    if (baseParticle.ContainsElement(elem))
                                    {
                                        fromBaseType = true;
                                    }
                                    else if (!typeInfo.InlineBaseType && baseType.ContainsName(elem.QualifiedName))
                                    {
                                        typeInfo.InlineBaseType = true;
                                    }

                                }
                                propertyInfo = BuildProperty(elem, fromBaseType);
                                regEx.Append(propertyInfo.PropertyName);
                                AppendOccurenceToRegex(propertyInfo, regEx);
                                //Add to parent
                                if (currentGroupingInfo == null)
                                {
                                    //Not adding property to propertyNameTypeTable as this case will occur only for pointless groups, so they have just one property
                                    BuildAnnotationInformation(propertyInfo, elem, false, false);
                                    typeInfo.AddMember(propertyInfo);
                                }
                                else
                                {
                                    BuildAnnotationInformation(propertyInfo, elem, currentGroupingInfo.ContentModelType == ContentModelType.Choice, currentGroupingInfo.IsNested);
                                    currentGroupingInfo.AddChild(propertyInfo);
                                    SetPropertyFlags(propertyInfo, currentGroupingInfo, elem.ElementSchemaType);
                                }
                                break;

                            }
                        case ParticleType.Any:
                            {
                                regEx.Append("any");
                                XmlSchemaAny any = particle as XmlSchemaAny;

                                if (derivationMethod == XmlSchemaDerivationMethod.Extension && typeInfo.IsDerived)
                                {
                                    if (baseParticle.ContainsWildCard(any))
                                    {
                                        typeInfo.HasElementWildCard = true;//ANY property in the base type will be reused
                                    }
                                }

                                //Note we always create a property info object to keep the original nesting structure in the schema
                                //so it can be used to create a correct FSM; on the other hand, typeInfo.HasElementWildCard will indicate whether
                                //we need to create a property in the resulting object type.
                                ClrWildCardPropertyInfo wcPropertyInfo = BuildAnyProperty(any, !typeInfo.HasElementWildCard);

                                //Add to parent
                                if (currentGroupingInfo == null)
                                {
                                    typeInfo.AddMember(wcPropertyInfo);
                                }
                                else
                                {
                                    currentGroupingInfo.AddChild(wcPropertyInfo);
                                }
                                if (!typeInfo.HasElementWildCard) typeInfo.HasElementWildCard = true;
                                break;
                            }

                        case ParticleType.Sequence:
                        case ParticleType.Choice:
                        case ParticleType.All:
                            regEx.Append("(");
                            if (currentGroupBase != null)
                            {
                                //already there is a group that we are processing, push it on stack to process sub-group
                                particleStack.Push(new ParticleData(currentGroupBase, currentGroupingInfo, currentIndex));
                                currentIndex = 0; //Re-start index for new group base
                            }
                            parentGroupInfo = currentGroupingInfo; //Assign parent before creating child groupInfo
                            currentGroupBase = particle as XmlSchemaGroupBase;
                            Debug.Assert(currentGroupBase != null);
                            currentGroupingInfo = new GroupingInfo((ContentModelType)((int)particleType), GetOccurence(currentGroupBase));

                            //Add to parent
                            if (parentGroupInfo == null)
                            {
                                typeInfo.AddMember(currentGroupingInfo);
                                parentGroupInfo = currentGroupingInfo; //Assign first time
                            }
                            else
                            {
                                parentGroupInfo.AddChild(currentGroupingInfo);
                                parentGroupInfo.HasChildGroups = true;
                                currentGroupingInfo.IsNested = true;
                                if (parentGroupInfo.IsRepeating)
                                {
                                    currentGroupingInfo.IsRepeating = true;
                                }
                                if (currentGroupingInfo.IsRepeating)
                                {
                                    parentGroupInfo.HasRepeatingGroups = true;
                                }
                            }
                            break;

                    }
                }
                //Drill down into items
                if (currentGroupBase != null && currentIndex < currentGroupBase.Items.Count)
                {
                    // if this isnt the first, then we need a seperator
                    if (currentIndex > 0)
                    {
                        regEx.Append(currentGroupingInfo.ContentModelType == ContentModelType.Choice ? " | " : ", ");
                    }
                    particle = (XmlSchemaParticle)currentGroupBase.Items[currentIndex++];
                }
                else
                {
                    if (currentGroupBase != null)
                    {
                        regEx.Append(")");
                        AppendOccurenceToRegex(currentGroupingInfo, regEx);
                    }

                    if (particleStack.Count > 0)
                    {
                        bool childGroupHasRecurringElements = currentGroupingInfo.HasRecurrentElements;
                        bool childGroupHasRepeatingGroups = currentGroupingInfo.HasRepeatingGroups;

                        particleData = particleStack.Pop();
                        currentGroupBase = particleData.currentGroupBase;
                        currentGroupingInfo = particleData.currentGroupingInfo;

                        currentGroupingInfo.HasRecurrentElements = childGroupHasRecurringElements;
                        currentGroupingInfo.HasRepeatingGroups = childGroupHasRepeatingGroups;

                        currentIndex = particleData.currentIndex;
                        if (currentIndex < currentGroupBase.Items.Count)
                        {
                            particle = (XmlSchemaParticle)currentGroupBase.Items[currentIndex++];
                            regEx.Append(currentGroupingInfo.ContentModelType == ContentModelType.Choice ? "|" : ", ");
                        }
                        else
                        {
                            // we were already at the end of the parent group, so just continue
                            currentIndex++; //we are off the end of this list
                        }
                    }
                    else
                    { //No more particles to process
                        break;
                    }
                }
            }
            if (regEx.Length != 0)
            {
                typeInfo.ContentModelRegEx = regEx.ToString();
            }
        }