QComboBox(下拉框)

QComboBox *comboBox = new QComboBox;
comboBox->addItem("Item 1");
comboBox->addItem("Item 2");
comboBox->addItem("Item 3");

// 连接信号和槽
QObject::connect(comboBox, QOverload<int>::of(&QComboBox::currentIndexChanged),
                 [=](int index)
                     qDebug() << "Selected item index: " << index;
                 });