How can I prevent QDialog class from closing

Question

How can I prevent QDialog class from closing after \"Ok\" button was pressed? I need to close the window only if the some actions were performed correctly on this dialog, in

Answer 1

The same as from @kuba-ober, but using custom property. Change one function:

void QDialogValidator::checkValidity(QLineEdit * l) {
  if (!l) return;
  QString text = l->text();
  int pos;
  bool isValid = l->validator()->validate(text, pos) == QValidator::Acceptable;
  setSelect(m_validWidgets, isValid, (QWidget*)l);
  if (!l->property("invalid").toBool() != isValid) {
    l->setProperty("invalid", !isValid);
    l->style()->unpolish(l);
    l->style()->polish(l);
  }
  emit newValidity(m_validWidgets.count() == m_needsValid);
}

Now styleSheet... functions are not necessary but we need to add constant style sheet for the dialog or application:

d.setStyleSheet("*[invalid=\"true\"] { background: yellow }");

Or if use Qt designer, add root widget property:

 *[invalid="true"] { border-style: solid; border-width: 1px; border-radius: 2px; border-color: yellow; }