System.Xml.Schema.SchemaCollectionPreprocessor.PreprocessParticle C# (CSharp) Method

        private void PreprocessParticle(XmlSchemaParticle particle) {
            if (particle is XmlSchemaAll) {
                if (particle.MinOccurs != decimal.Zero && particle.MinOccurs != decimal.One) {
                    particle.MinOccurs = decimal.One;
                    SendValidationEvent(Res.Sch_InvalidAllMin, particle);
                }
                if (particle.MaxOccurs != decimal.One) {
                    particle.MaxOccurs = decimal.One;
                    SendValidationEvent(Res.Sch_InvalidAllMax, particle);
                }
                foreach(XmlSchemaElement element in ((XmlSchemaAll)particle).Items) {
                    if (element.MaxOccurs != decimal.Zero && element.MaxOccurs != decimal.One) {
                        element.MaxOccurs = decimal.One;
                        SendValidationEvent(Res.Sch_InvalidAllElementMax, element);
                    }
                    SetParent(element, particle);
                    PreprocessLocalElement(element);
                }
            } 
            else {
                if (particle.MinOccurs > particle.MaxOccurs) {
                    particle.MinOccurs = particle.MaxOccurs;
                    SendValidationEvent(Res.Sch_MinGtMax, particle);
                }
                if (particle is XmlSchemaChoice) {
                    foreach(XmlSchemaObject item in ((XmlSchemaChoice)particle).Items) {
                        SetParent(item, particle);
                        if (item is XmlSchemaElement) {
                            PreprocessLocalElement((XmlSchemaElement)item);
                        } 
                        else {
                            PreprocessParticle((XmlSchemaParticle)item);
                        }
                    }
                } 
                else if (particle is XmlSchemaSequence) {
                    foreach(XmlSchemaObject item in ((XmlSchemaSequence)particle).Items) {
                        SetParent(item, particle);
                        if (item is XmlSchemaElement) {
                            PreprocessLocalElement((XmlSchemaElement)item);
                        } 
                        else {
                            PreprocessParticle((XmlSchemaParticle)item);
                        }
                    }
                } 
                else if (particle is XmlSchemaGroupRef) {
                    XmlSchemaGroupRef groupRef = (XmlSchemaGroupRef)particle;
                    if (groupRef.RefName.IsEmpty) {
                        SendValidationEvent(Res.Sch_MissAttribute, "ref", groupRef);
                    }
                    else {
                        ValidateQNameAttribute(groupRef, "ref", groupRef.RefName);
                    }
                } 
                else if (particle is XmlSchemaAny) {
                    try {
                        ((XmlSchemaAny)particle).BuildNamespaceListV1Compat(this.targetNamespace);
                    } 
                    catch {
                        SendValidationEvent(Res.Sch_InvalidAny, particle);
                    }
                }
            }
            PreprocessAnnotation(particle); //set parent of annotation child of group / all/ choice / sequence
            ValidateIdAttribute(particle);
        }