为什么我的信号不触发没有Qt：:D irectConnection的插槽？

我有一个主类，它启动一个执行单个操作的线程。我正在尝试捕捉线程操作何时完成。

主类:

// .h
class MainClass : public QObject
{
    Q_OBJECT
public:
    QThread thread;
// ...
public slots:
    void onFinish();
}
// .cpp
void MainClass::startThread()
{
    thread = new QThread();
    worker = new Worker();
    worker->moveToThread(thread);
    connect(thread, SIGNAL(started()), worker, SLOT(process()));
    connect(worker, SIGNAL(finished()), thread, SLOT(quit()));
    connect(worker, SIGNAL(finished()), worker, SLOT(deleteLater()));
    connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
    connect(worker, SIGNAL(finished()), this, SLOT(onFinish()));
    // connect(worker, SIGNAL(finished()), this, SLOT(onFinish()), Qt::DirectConnection);
}
void MainClass::onFinish()
{
    std::cout << "Finished!" << std::endl << std::flush;
}

线程的Worker类:

// .h
class Worker : public QObject
{
    Q_OBJECT
public:
    explicit Worker(QObject *parent = 0);
    ~Worker();
public slots:
    void process();
signals:
    void finished();
}
// .cpp
void Worker::process()
{
    // ...Do stuff...
    emit finished();
}

执行startThread不打印"Finished!"为什么?

我注意到，如果我将Qt::DirectConnection添加到连接到onFinish()的行(如在注释行中)，则打印消息。但是，如果我想在主类的线程中执行onFinish()动作，我能做些什么呢?

编辑1

此外，似乎finished() -> quit()连接也不起作用，因为如果我调用thread->isFinished()或thread->isRunning()，在主线程睡眠后确保线程任务完成，我分别获得false和true。

编辑2

因为它也可能是相关的，这里是main.cpp:

int _tmain(int argc, _TCHAR* argv[])
{
    QCoreApplication a(argc, argv);
    std::unique_ptr <MainClass> mc = std::make_unique <MainClass>();
    mc->startThread();
    mc->thread->wait();
    return a.exec();
}