JSON array in Delphi

Question

I have to place a JSON string to a HTTP request's body. One of the string value must be a JSON array. This is how I tried:

uses
  DBXJSON;

const
  cContent = 'hello world';
var
  LJSONObject: TJSONObject;
  x: TBytes;
  i: integer;
  Temp: string;
begin
  LJSONObject:= TJSONObject.Create;
  LJSONObject.AddPair('id1', 'value1');
  LJSONObject.AddPair('id2', 'value2');
  LJSONObject.AddPair('id2', 'value3');

  x:= TEncoding.ANSI.GetBytes(cContent);
  Temp:= '';
  for i := 0 to Length(x) - 1 do
    Temp:= Temp + IntToStr(x[i]) + ',';
  Delete(Temp, Length(Temp), 1);

  LJSONObject.AddPair('id4', '[' + Temp + ']');

  ShowMessage(LJSONObject.ToString);
end;

This one is not working, because the value will be encapsulated in double quotes. What is the proper way to pass an array value to the JSONObject?

You are passing a string. Pass a TJSONArray. What you are doing is weird though. ANSI? Why an array anyway. The content is a string. — David Heffernan
– David Heffernan, Commented Aug 3, 2015 at 5:19
The receiver side is waiting for array. I know I should pass an Array, but I dont know how. This is a test code, don't worry about the ANSI :) — tcxbalage
– tcxbalage, Commented Aug 3, 2015 at 5:29

David Heffernan · Accepted Answer · 2015-08-03 05:59:14Z

2

You are passing a string rather than an array. Hence the result you observe. As a rule, if you find yourself assembling the JSON manually, you are doing it wrong.

Pass an array:

var
  arr: TJSONArray;
  b: Byte;
....
arr := TJSONArray.Create;
for b in TEncoding.ANSI.GetBytes(cContent) do
  arr.Add(b);
LJSONObject.AddPair('id4', arr);

edited Aug 3, 2015 at 5:59

answered Aug 3, 2015 at 5:30

David Heffernan

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3 Comments

tcxbalage Over a year ago

I have tried similar solution, the problem is the "arr.AddElement(b)". Compiler says "Incompatible types: TJSonValue an Byte". The addElement() accept TJSonValue param only. I'm using XE4 if it matters.

David Heffernan Over a year ago

Sorry, the method is Add

tcxbalage Over a year ago

Works fine! Thanks a lot.

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