[Lazarus] Convert record to JSON?

[Bo Berglund]

On Fri, 20 Jul 2018 19:33:19 +0200, Bo Berglund via Lazarus
<lazarus at lists.lazarus-ide.org> wrote:

I changed my code now so my recrd is instead an object:

type TMyRecord = Class(TObject)
    checksum: word;
    ssid: AnsiString;
    passwd: AnsiString;
    macaddr: AnsiString;
    addr: TIpAddress;
    baud: integer;
    tcpport: word;
    mode: byte;
    channel: byte;
    hidden: byte;  // hidden (1) or visible (0)
    fixedaddress: byte; //Station mode fixed addr instead of DHCP
    numsensors: byte; //Number of active DHT sensors (0..3)
    dhtinterval: word;  // Interval between DHT sensor readings (min)
    host: AnsiString; 
  end;

I also changed my function to create the JSON string:

function RecToJSON(RC: TMyrecord): string;
var
  JS: TJSONStreamer;
begin
  JS := TJSONStreamer.Create(NIL);
  try
    JS.Options := JS.Options + [jsoTStringsAsArray];
    Result := JS.ObjectToJSONString(RC);
  finally
    JS.Free;
  end;
end;

When I run this code in my existing application I can step into the
line
   Result := JS.ObjectToJSONString(RC);
and hover the mouse over RC and it displays the correct values for all
fields of the object.

But when the line executes the result is a string with only this empty
content:

{}

Why is this?
What have I done wrong?

-- 
Bo Berglund
Developer in Sweden