소스는 아래와 같습니다. 스레드를 사용하지 않으면 잘되는데 스레드를 사용하면 변수 값이 변경됩니다.

procedure TForm1.Button4Click(Sender: TObject);
var
  AThread : TEventRunTherad;
  sTime, sEventNm, AEventType: string;
begin
  AEventType := cbotype.Text;

  AThread := TEventRunTherad.Create(True);
  AThread.ATUrl        := PChar(Trim(edtUrl.Text));
  AThread.ATDeviceId   := PChar(Trim(edtDeviceId.Text));
  AThread.ATToken      := PChar(Trim(edtToken.Text));
  AThread.ATStoreCd    := PChar(Trim(edtStorecd.Text));
  AThread.ATEventType  := PChar(AEventType);

  AThread.Resume;
end;

{ TEventRunTherad }

procedure TEventRunTherad.Execute;
type
  TGageEventAdd=function(AUrl, ADeviceId, AToken, AStoreCd, AEventType: PChar): PAnsiChar; stdcall;
var
  GageEventAdd: TGageEventAdd;
  HNtdll: Cardinal;
  sTmp: string;
begin
 

  HNtdll := LoadLibrary('Gage119.DLL');
  if(HNtdll = 0) then
  begin
    ShowMessage('DLL을 찾을 수 없습니다.');
    Self.Terminate;
    Self.Free;
    exit;
  end;
  GageEventAdd:=GetProcAddress(HNtdll,'GageEventAdd');
  sTmp := GageEventAdd(ATUrl, ATDeviceId, ATToken, ATStoreCd, ATEventType );
  if sTmp = 'false' then
  begin
    showmessage('이벤트등록 실패');
    sTmp := GageEventAdd(ATUrl, ATDeviceId, ATToken, ATStoreCd, ATEventType );
    if sTmp = 'false' then
    begin
      showmessage('이벤트등록 실패');
    end
    else
    begin
      showmessage('이벤트등록 성공');
    end;
  end
  else
  begin
    showmessage(sTmp);
    showmessage('이벤트등록 성공');
  end;
  Self.Terminate;
  Self.Free;

  inherited;
end;