(Delphi ActiveX) Loading and Parsing a JSON Array

A JSON array is JSON that begins with "[" and ends with "]". For example, this is a JSON array that contains 3 JSON objects.

[{"name":"jack"},{"name":"john"},{"name":"joe"}]

A JSON object, however, is JSON that begins with "{" and ends with "}". For example, this JSON is an object that contains an array.

{"pets":[{"name":"jack"},{"name":"john"},{"name":"joe"}]}

This example shows how loading a JSON array is different than loading a JSON object.

Chilkat for Delphi Downloads

Chilkat ActiveX DLL for Delphi

Chilkat non-ActiveX DLL for Delphi

* The examples here use the ActiveX DLL.

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
strJsonArray: WideString;
strJsonObject: WideString;
jsonArray: TChilkatJsonArray;
i: Integer;
jsonObj: IChilkatJsonObject;
jsonObject: TChilkatJsonObject;
numPets: Integer;

begin
strJsonArray := '[{"name":"jack"},{"name":"john"},{"name":"joe"}]';

strJsonObject := '{"pets":[{"name":"jack"},{"name":"john"},{"name":"joe"}]}';

// A JSON array must be loaded using JsonArray:
jsonArray := TChilkatJsonArray.Create(Self);
jsonArray.Load(strJsonArray);

// Examine the values:
i := 0;
while i < jsonArray.Size do
  begin
    jsonObj := jsonArray.ObjectAt(i);
    Memo1.Lines.Add(IntToStr(i) + ': ' + jsonObj.StringOf('name'));

    i := i + 1;
  end;

// Output is:

// 	0: jack
// 	1: john
// 	2: joe

// A JSON object must be loaded using JsonObject
jsonObject := TChilkatJsonObject.Create(Self);
jsonObject.Load(strJsonObject);

// Examine the values:
i := 0;
numPets := jsonObject.SizeOfArray('pets');
while i < numPets do
  begin
    jsonObject.I := i;
    Memo1.Lines.Add(IntToStr(i) + ': ' + jsonObject.StringOf('pets[i].name'));
    i := i + 1;
  end;

// Output is:

// 	0: jack
// 	1: john
// 	2: joe
end;