qt - QWebChannel 如何返回自定义数据结构

Question

基于 qtqwebenginepage::setwebchannel() 传输对象和 QT: 无法从 JavaScript 调用返回自定义数据结构。我需要这个功能，但我不知道该怎么做。

/** this is my data type */
class QDataDictionary {
public:
    QString number;
    QString name;
    QString description;
};

Q_DECLARE_METATYPE(QDataDictionary);

希望接口处理完相关操作后能返回自己定义的数据。以下是我的C++实现代码

#ifndef QSYSTEMDICTIONARYMANAGER_H
#define QSYSTEMDICTIONARYMANAGER_H

#include <QObject>
#include "qsystemdatadictionary.h"

class QSystemDictionaryManager : public QObject
{
    Q_OBJECT
public:
    explicit QSystemDictionaryManager(QObject *parent = nullptr);
    virtual ~QSystemDictionaryManager();

signals:

public slots:
    /** I want to return this data structure */
    Q_INVOKABLE QDataDictionary debug(const QString& contents);

public slots:

protected:
};

#endif // QSYSTEMDICTIONARYMANAGER_H

#include "qsystemdictionarymanager.h"
#include <QTextStream>
#include <QMessageBox>

QSystemDictionaryManager::QSystemDictionaryManager(QObject *parent) : QObject(parent)
{

}

QSystemDictionaryManager::~QSystemDictionaryManager() {

}

QDataDictionary data;
QDataDictionary QSystemDictionaryManager::debug(const QString &contents)
{
    QString DebugMessage;
    QTextStream DebugTextStream(&DebugMessage);
    DebugTextStream << this << " " << __LINE__ << " "<< __FUNCTION__ << " == " << contents;
    QMessageBox::information(nullptr, "javascrpt call authenticate", DebugMessage);


    data.number = "256";
    data.name = "___dictionary__";
    data.description = "QSystemDataDictionary";
    return data;
}

下面是我通过JavaScript调用C++的接口，但是没有得到我想要返回的数据

var SystemDictionaryManager;
        new QWebChannel(qt.webChannelTransport,
            function (channel) {
                SystemDictionaryManager = channel.objects.SystemDictionaryManager;
            });
        var debug = async function (text) {
            if (typeof SystemDictionaryManager !== "undefined") {
                var message = "System Dictionary Manager";
                /** Calling the interface can't get the data I want */
                await new Promise(resolve =>
                    SystemDictionaryManager.debug(message, function (result) {
                        document.getElementById("main").innerHTML = "data is == " + result;
                        resolve();
                    }));
            }
        }