你在QFileDialog中看到的,并不是Qt实现的对话框,而是调用的系统现成的对话框。
QFileDialog::DontUseNativeDialog
Don't use the native file dialog. By default, the native file dialog is used unless you use a subclass of QFileDialog that contains the Q_OBJECT macro, or the platform does not have a native dialog of the type that you require.