System.Runtime.Serialization.Json.DataContractJsonSerializerImpl.GetDataContract C# (CSharp) Method

        internal static DataContract GetDataContract(DataContract declaredTypeContract, Type declaredType, Type objectType)
        {
            DataContract contract = DataContractSerializer.GetDataContract(declaredTypeContract, declaredType, objectType);
            CheckIfTypeIsReference(contract);
            return contract;
        }
    }

        internal override void InternalWriteObjectContent(XmlWriterDelegator writer, object graph)
        {
            if (MaxItemsInObjectGraph == 0)
            {
                throw XmlObjectSerializer.CreateSerializationException(SR.Format(SR.ExceededMaxItemsQuota, MaxItemsInObjectGraph));
            }

            DataContract contract     = RootContract;
            Type         declaredType = contract.UnderlyingType;
            Type         graphType    = (graph == null) ? declaredType : graph.GetType();

            //if (dataContractSurrogate != null)
            //{
            //    graph = DataContractSerializer.SurrogateToDataContractType(dataContractSurrogate, graph, declaredType, ref graphType);
            //}

            if (graph == null)
            {
                WriteJsonNull(writer);
            }
            else
            {
                if (declaredType == graphType)
                {
                    if (contract.CanContainReferences)
                    {
                        XmlObjectSerializerWriteContextComplexJson context = XmlObjectSerializerWriteContextComplexJson.CreateContext(this, contract);
                        context.OnHandleReference(writer, graph, true); //  canContainReferences
                        context.SerializeWithoutXsiType(contract, writer, graph, declaredType.TypeHandle);
                    }
                    else
                    {
                        DataContractJsonSerializerImpl.WriteJsonValue(JsonDataContract.GetJsonDataContract(contract), writer, graph, null, declaredType.TypeHandle); //  XmlObjectSerializerWriteContextComplexJson
                    }
                }
                else
                {
                    XmlObjectSerializerWriteContextComplexJson context = XmlObjectSerializerWriteContextComplexJson.CreateContext(this, RootContract);
                    contract = DataContractJsonSerializerImpl.GetDataContract(contract, declaredType, graphType);
                    if (contract.CanContainReferences)
                    {
                        context.OnHandleReference(writer, graph, true); //  canContainCyclicReference
                        context.SerializeWithXsiTypeAtTopLevel(contract, writer, graph, declaredType.TypeHandle, graphType);
                    }
                    else
                    {
                        context.SerializeWithoutXsiType(contract, writer, graph, declaredType.TypeHandle);
                    }
                }
            }
        }