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Programming => General => Topic started by: franko_nd on February 03, 2023, 12:31:29 pm

Title: Serialize/DeSerialize generic.collection type to from JSON
Post by: franko_nd on February 03, 2023, 12:31:29 pm

Hello!

Help, please.

System OS Windows 7 x64.
FPC 3.3.1 in CodeTyphon 8.0.

I have JSON (TJSOnData) :
[{ "id" : "87DC528AF55142CFBB019D98F5ABD0D8", "value" : 178 }, { "id" : "37A2B479C1BE46E8BBC11E05C5BAB75C", "value" : 89 }, { "id" : "7BBA5B77595A4141B7E994473CDAFE39", "value" : 16 }, { "id" : "9A946B8A373344ADBD789D75E7572A03", "value" : 80 }, { "id" : "665D45735D354DBF9A0C665E07BBEA7E", "value" : 90 }]

Need deserialize this JSON to TListValueBaseParam = class(TList<TValueBaseParam>).
And need serialize TListValueBaseParam to JSON.

Description class :

  TValueBaseParam = record
   ID                 : String;
   Value              : Double;
   procedure Clear();
  end;

  TListValueBaseParam = class(TList<TValueBaseParam>)
   function IndexOfID(ID: String): Integer;overload;
   procedure ToMemory(MemData: TMemoryStream);
   procedure FromMemory(MemData: TMemoryStream);
   ...
  end;

Title: Re: Serialize/DeSerialize generic.collection type to from JSON
Post by: Zvoni on February 03, 2023, 01:12:06 pm

Quote from: franko_nd on February 03, 2023, 12:31:29 pm

FPC 3.3.1 in CodeTyphon 8.0.

Ask in CodeTyphoon-Forum....

Title: Re: Serialize/DeSerialize generic.collection type to from JSON
Post by: paweld on February 03, 2023, 01:25:00 pm

I don't know how to deserialize to generics.collection, but an example of deserialization to TCollection is in the appendix. 

Edit: if you don't want to save the TCollection to an object, but directly as an array then modify the procedure that saves to JSON to:

Code: Pascal  [Select][+][-]

1. function TListValueBaseParam.SaveToJSON: String;var
2.   js: TJSONStreamer;
3. begin
4.   Result := '';
5.   js := TJSONStreamer.Create(nil);
6.   try
7.     Result := js.CollectionToJSON(Self); //instead of: js.ObjectToJSONString(Self);
8.   except
9.     js.Free;
10.   end;
11. end;
12.