如何将参数从Qml传递到C++？

// DataBridge.h
#ifndef DATABRIDGE_H
#define DATABRIDGE_H

#include <QObject>

class DataBridge : public QObject
{
    Q_OBJECT
public:
    explicit DataBridge(QObject *parent = nullptr);

signals:
    void dataChanged(const QString &data);

public slots:
    void sendDataToCpp(const QString &data);
};

#endif // DATABRIDGE_H

// DataBridge.cpp
#include "DataBridge.h"

DataBridge::DataBridge(QObject *parent) : QObject(parent)
{
}

void DataBridge::sendDataToCpp(const QString &data)
{
    emit dataChanged(data);
}

import QtQuick 2.0

Item {
    id: root

    // 导入C++类
    import com.example 1.0

    // 创建DataBridge实例
    DataBridge {
        id: dataBridge
    }

    // 定义一个属性来接收从C++传递过来的参数
    property string receivedData: ""

    // 通过信号和槽将参数从QML传递到C++
    function sendDataToCpp(data) {
        dataBridge.sendDataToCpp(data)
    }

    // 接收从C++传递过来的参数
    Connections {
        target: dataBridge
        onDataChanged: {
            root.receivedData = data
        }
    }
}

// main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include "DataBridge.h"

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

    QQmlApplicationEngine engine;

    // 注册DataBridge类
    qmlRegisterType<DataBridge>("com.example", 1, 0, "DataBridge");

    const QUrl url(QStringLiteral("qrc:/main.qml"));
    engine.load(url);

    return app.exec();
}