QListWidget如何发出信号？

#include <QApplication>
#include <QListWidget>
#include <QListWidgetItem>
#include <QMessageBox>

class MyListWidget : public QListWidget {
public:
    MyListWidget(QWidget *parent = nullptr) : QListWidget(parent) {
        connect(this, &QListWidget::itemClicked, this, &MyListWidget::onItemClicked);
    }

private slots:
    void onItemClicked(QListWidgetItem *item) {
        QMessageBox::information(this, "Item Clicked", QString("You clicked: %1").arg(item->text()));
    }
};

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);

    MyListWidget listWidget;
    listWidget.addItem(new QListWidgetItem("Item 1"));
    listWidget.addItem(new QListWidgetItem("Item 2"));
    listWidget.addItem(new QListWidgetItem("Item 3"));
    listWidget.show();

    return app.exec();
}