Pascal (Lazarus/Delphi)

JSON: Nested Objects

See more JSON Examples

Here we have a JSON object that contains nested JSON objects. This example demonstrates how to access the contents of the nested objects.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.JsonObject;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  json: TJsonObject;
  jsonStr: string;
  imageObj: TJsonObject;
  thumbObj: TJsonObject;

begin
  success := False;

  json := TJsonObject.Create;

  //  This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
  //  The presence of whitespace chars for pretty-printing makes no difference to the Load
  //  method. 
  jsonStr := '{"name": "donut","image":{"fname": "donut.jpg","w": 200,"h": 200},"thumbnail":{"fname": "donutThumb.jpg","w": 32,"h": 32}}';

  success := json.Load(jsonStr);
  if (success = False) then
    begin
      WriteLn(json.LastErrorText);
      Exit;
    end;

  //  Get the "image" object.
  imageObj := TJsonObject.Create;
  json.ObjectOf2('image',imageObj);

  WriteLn('image: fname=' + imageObj.StringOf('fname') + ', width=' + imageObj.IntOf('w') + ', height=' + imageObj.IntOf('h'));

  //  Get the "thumbnail" object.
  thumbObj := TJsonObject.Create;
  json.ObjectOf2('thumbnail',thumbObj);

  WriteLn('thumbnail: fname=' + thumbObj.StringOf('fname') + ', width=' + thumbObj.IntOf('w') + ', height=' + thumbObj.IntOf('h'));


  json.Free;
  imageObj.Free;
  thumbObj.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.