Delphi ActiveX

Get the Root of a JSON Document

See more JSON Examples

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

Delphi ActiveX

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
json: TChilkatJsonObject;
jsonStr: WideString;
abcObj: TChilkatJsonObject;
xArray: TChilkatJsonArray;
bObj: TChilkatJsonObject;
docRoot: TChilkatJsonObject;

begin
success := 0;

json := TChilkatJsonObject.Create(Self);

jsonStr := '{"flower": "tulip","abc":{"x": [{ "a" : 1 },{ "b1" : 100, "b2" : 200 },{ "c" : 3 }],"y": 200,"z": 200}}';

success := json.Load(jsonStr);
if (success = 0) then
  begin
    Memo1.Lines.Add(json.LastErrorText);
    Exit;
  end;

// Get the "abc" object.
abcObj := TChilkatJsonObject.Create(Self);
success := json.ObjectOf2('abc',abcObj.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(json.LastErrorText);
    Exit;
  end;

// Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
abcObj.EmitCompact := 0;
Memo1.Lines.Add(abcObj.Emit());

// Navigate to the "x" array
xArray := TChilkatJsonArray.Create(Self);
abcObj.ArrayOf2('x',xArray.ControlInterface);

// Navigate to the 2nd object contained within the array.  This contains members b1 and b2
bObj := TChilkatJsonObject.Create(Self);
xArray.ObjectAt2(1,bObj.ControlInterface);

// Show that we're at "b1/b2".
// The value of "b1" should be "200"
Memo1.Lines.Add('b2 = ' + IntToStr(bObj.IntOf('b2')));

// Now go back to the JSON doc root:
docRoot := TChilkatJsonObject.Create(Self);
bObj.GetDocRoot2(docRoot.ControlInterface);

// We'll skip the null check and assume it's non-null...

// Pretty-print the JSON doc from the root to show that this is indeed the root.
docRoot.EmitCompact := 0;
Memo1.Lines.Add(docRoot.Emit());
end;