Custom service using JSON string type in D365 F&O

[DataContract]

class JSONContract

{

    String50 parmFirst, parmSecond;

    List     lines = new  List (types::Class);

    [

        DataMemberAttribute('parmFirst')

    ]

    public String50 parmFirst(String50 _parmFirst = parmFirst)

    {

        parmFirst = _parmFirst;

        return parmFirst;

    }

    [

        DataMemberAttribute('parmSecond')

    ]

    public String50 parmSecond(String50 _parmSecond = parmSecond)

    {

        parmSecond = _parmSecond;

        return parmSecond;

    }

    [DataMemberAttribute('lines'),

    DataCollectionattribute(types::class, classstr(JSONLineContract))]

    public List parmLines(List _lines = lines)

    {

        lines = _lines;

        return lines;

    }

}

[DataContract]

class JSONLineContract

{

    String50 parmFirst, parmSecond;

    [

        DataMemberAttribute('parmFirst')

    ]

    public String50 parmFirst(String50 _parmFirst = parmFirst)

    {

        parmFirst = _parmFirst;

        return parmFirst;

    }

    [

        DataMemberAttribute('parmSecond')

    ]

    public String50 parmSecond(String50 _parmSecond = parmSecond)

    {

        parmSecond = _parmSecond;

        return parmSecond;

    }

}

class ReadJson

{

    public static void main(Args _args)

    {

        str json;

        List values = new List(Types::Class);

  List valuesLines = new List(Types::Class);

        ListEnumerator value,valueLines;

        json = '[{"FieldValues": [{"parmFirst": "ValueFirst", "parmSecond": "ValueSecond", "lines":[{"parmFirst": "ValueFirst1", "parmSecond": "ValueSecond1"},{"parmFirst": "ValueFirst2", "parmSecond": "ValueSecond2"}] }]}]';

        values = FormJsonSerializer::deserializeCollection(classnum(List), json, Types::Class, classStr(JSONContract));

        value = values.getEnumerator();

        while(value.moveNext())

        {

            JSONContract JSONContractCurrent = value.current();

            info(strfmt('%1',JSONContractCurrent.parmFirst(), JSONContractCurrent.parmSecond()));

            valuesLines = JSONContractCurrent.parmLines();

valueLines = valuesLines.getEnumerator();

            while(valueLines.moveNext())

            {

JSONLineContract JSONLineContractCurrent = valueLines.current();

info(strfmt('%1',JSONLineContractCurrent.parmFirst(), JSONLineContractCurrent.parmSecond()));

}

        }

    }

}