Disappearing SubDetail TObjectList when JSonToObject - json

Question

this is my first question. Sorry my english.
I have a classes like this:
TSFis_S = class(TPersistent)
private
_SFis_MID : Integer;
public
property SFis_MID : Integer read _SFis_MID write _SFis_MID;
end;
TSFis_D = class(TPersistent)
private
_SFis_MID : Integer;
_SFis_S : TObjectList<TSFis_S>;
public
property SFis_MID : Integer read _SFis_MID write _SFis_MID;
property SFis_S : TObjectList<TSFis_S> read _SFis_S write _SFis_S;
end;
TSFis_M = class(TPersistent)
private
_SFis_MID : Integer;
_SFis_D : TObjectList<TSFis_D>;
public
property SFis_MID : Integer read _SFis_MID write _SFis_MID;
property SFis_D : TObjectList<TSFis_D> read _SFis_D write _SFis_D;
function ToJSON:TJSONValue;
destructor Destroy;
end;
I trying convert TSFis_M Object to JSon and Revert to Object for my datasnap application. I use converts and reverters for my datatypes (TObjectList and TObjectList)
{ TSFis_M }
function JSonToSFis_M(json: TJSONValue): TSFis_M;
var
UnMarshaller: TJSONUnMarshal;
begin
if json is TJSONNull then
exit(nil);
UnMarshaller := TJSONUnMarshal.Create;
try
UnMarshaller.RegisterReverter(TSFis_M, '_FisTar',
procedure(Data: TObject; Field: string; Arg: string)
var
ctx: TRttiContext;
datetime :
TDateTime;
begin
datetime := EncodeDateTime(StrToInt(Copy(Arg, 7, 4)), StrToInt(Copy(Arg, 4, 2)), StrToInt(Copy(Arg, 1, 2)), StrToInt
(Copy(Arg, 12, 2)), StrToInt(Copy(Arg, 15, 2)), StrToInt(Copy(Arg, 18, 2)), 0);
ctx.GetType(Data.ClassType).GetField(Field).SetValue(Data, datetime);
end
);
UnMarshaller.RegisterReverter(TSFis_D, '_SFis_S',
procedure(Data: TObject; Field: String; Args: TListOfObjects)
var
obj: TObject;
SFisS: TObjectList<TSFis_S>;
SFis, SFisNew: TSFis_S;
begin
if TSFis_D(Data)._SFis_S=Nil
then TSFis_D(Data)._SFis_S := TObjectList<TSFis_S>.Create(True);
SFisS := TSFis_D(Data)._SFis_S;
SFisS.Clear;
for obj in Args do
begin
SFis := obj as TSFis_S;
SFisNew := TSFis_S.Create;
SFisS.Add(SFisNew);
SFisNew._SFis_MID := SFis._SFis_MID;
end;
end
);
UnMarshaller.RegisterReverter(TSFis_M, '_SFis_D',
procedure(Data: TObject; Field: String; Args: TListOfObjects)
var
obj: TObject;
SFisD: TObjectList<TSFis_D>;
SFis, SFisNew: TSFis_D;
i: integer;
begin
if TSFis_M(Data)._SFis_D=Nil then
TSFis_M(Data)._SFis_D := TObjectList<TSFis_D>.Create(True);
SFisD := TSFis_M(Data)._SFis_D;
SFisD.Clear;
for obj in Args do
begin
SFis := obj as TSFis_D;
SFisNew := TSFis_D.Create;
SFisD.Add(SFisNew);
SFisNew._SFis_MID := SFis._SFis_MID;
end;
end
);
exit(Unmarshaller.Unmarshal(json) as TSFis_M)
finally
UnMarshaller.Free;
end;
end;
function TSFis_M.ToJSON: TJSONValue;
var
Marshaller: TJSONMarshal;
begin
if Assigned(Self) then
begin
Marshaller := TJSONMarshal.Create(TJSONConverter.Create);
try
Marshaller.RegisterConverter(TSFis_M, '_SFis_D',
function(Data: TObject; Field: String): TListOfObjects
var
FisD: TObjectList<TSFis_D>;
i: integer;
begin
FisD := TSFis_M(Data)._SFis_D;
SetLength(Result, FisD.Count);
if FisD.Count > 0 then
for I := 0 to FisD.Count - 1 do
Result[I] := FisD[i];
end);
Marshaller.RegisterConverter(TSFis_M, '_FisTar',
function(Data: TObject; Field: string): string
var
ctx: TRttiContext; date : TDateTime;
begin
date := ctx.GetType(Data.ClassType).GetField(Field).GetValue(Data).AsType<TDateTime>;
Result := FormatDateTime('dd.mm.yyyy hh:nn:ss', date);
end);
Marshaller.RegisterConverter(TSFis_D, '_SFis_S',
function(Data: TObject; Field: String): TListOfObjects
var
FisD: TObjectList<TSFis_S>;
i: integer;
begin
FisD := TSFis_D(Data)._SFis_S;
SetLength(Result, FisD.Count);
if FisD.Count > 0 then
for I := 0 to FisD.Count - 1 do
Result[I] := FisD[i];
end);
exit(Marshaller.Marshal(Self))
finally
Marshaller.Free;
end;
end
else
exit(TJSONNull.Create);
end;
And finally
for example i put 1 Button and 2 Memo on the form. And i try My created Object convert to Json, Json.ToString to Memo1. And Convert that JSonValue to Object.
procedure TForm1.Button1Click(Sender: TObject);
var
MainFis : TSFis_M;
MainFis2 : TSFis_M;
DFis : TSFis_D;
SFis : TSFis_S;
begin
MainFis := TSFis_M.Create;
MainFis.SFis_D := TObjectList<TSFis_D>.Create(True);
DFis := TSFis_D.Create;
DFis._SFis_MID := 1;
MainFis.SFis_D.Add(DFis);
SFis := TSFis_S.Create;
SFis._SFis_MID := 1;
DFis.SFis_S := TObjectList<TSFis_S>.Create(True);
DFis.SFis_S.Add(SFis);
Memo1.Text := MainFis.ToJSON.ToString;
Edit1.Text := IntToStr(MainFis.SFis_D[0].SFis_S.Count);
MainFis2 := JSonToSFis_M(MainFis.ToJSON);
Edit2.Text := IntToStr(MainFis2.SFis_D[0].SFis_S.Count); // Access violation. Because MainFis2.SFis_D[0].SFis_S = Nil Now (That's the my problem. Why?)
Memo2.Text := MainFis2.ToJSon.ToString;
end;
But when i do this. TSFis_S is disappearing. In first step (ObjectToJSon) no problem.
{"type":"Unit1.TSFis_M","id":1,"fields":
{"_SFis_MID":0,"_SFis_D":
[ {"type":"Unit1‌​.TSFis_D","id":2,"fields":
{"_SFis_MID":1,"_SFis_S":
[ {"type":"Unit1.TSFis_S","id":‌​3,"fields":{"_SFis_MID":1} } ]
}
} ]
}
}
But when i trying revert to Object reverter goes wrong.
I can't found problem. What's my fault.
Thanks
PS: If i didn't explain, sample code here: http://goo.gl/3QnSw