SignalTest

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.12
import com.test.generator 1.0

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    Generator{
        id: generator
    }

    FlickableTextEdit{
        id: edit
        x: 5
        y: 5
        width: 50
        height: 20
    }

    ComboBox{
        x: 80
        y: 5
        id: combo
        property var obj
        model: ListModel {
                id: model
                ListElement { text: "Parameter1" }
                ListElement { text: "Parameter2" }
        }
        onActivated: {
            if(obj) obj.destroy();
            let pref;
            if(currentIndex === 0){
                pref = "1"
            }
            else{
                pref = "2"
            }
            obj = Qt.createQmlObject("import QtQuick 2.12; Connections{ target: generator; onParameter"+pref+"Changed: edit.text = value; }", edit, "Connection");
        }
    }
}

//generator.h
#ifndef GENERATOR_H
#define GENERATOR_H

#include <QObject>
#include <QTimer>

class Generator : public QObject
{
    Q_OBJECT
    Q_PROPERTY(double parameter1 READ parameter1 WRITE setParameter1 NOTIFY parameter1Changed)
    Q_PROPERTY(double parameter2 READ parameter2 WRITE setParameter2 NOTIFY parameter2Changed)
public:
    explicit Generator(QObject *parent = nullptr);

    double parameter1() const;
    void setParameter1(double parameter1);

    double parameter2() const;
    void setParameter2(double parameter2);

private:
    double m_parameter1;
    double m_parameter2;

    QTimer timer1;
    QTimer timer2;

signals:
    void parameter1Changed(double value);
    void parameter2Changed(double value);

public slots:
    void increase();
    void decrease();

};

#endif // GENERATOR_H

//generator.cpp
#include "generator.h"

Generator::Generator(QObject *parent) : QObject(parent)
{
    m_parameter1 = 0;
    m_parameter2 = 100000;
    connect(&timer1, SIGNAL(timeout()), this, SLOT(increase()));
    connect(&timer2, SIGNAL(timeout()), this, SLOT(decrease()));
    timer1.start(1000);
    timer2.start(1000);
}

double Generator::parameter1() const
{
    return m_parameter1;
}

void Generator::setParameter1(double ascending)
{
    m_parameter1 = ascending;
    emit parameter1Changed(m_parameter1);
}

double Generator::parameter2() const
{
    return m_parameter2;
}

void Generator::setParameter2(double descending)
{
    m_parameter2 = descending;
    emit parameter2Changed(m_parameter2);
}

void Generator::increase()
{
    m_parameter1++;
    if(m_parameter1 > 100000) m_parameter1 = 0;
    emit parameter1Changed(m_parameter1);
}

void Generator::decrease()
{
    m_parameter2--;
    if(m_parameter2 < 0) m_parameter2 = 100000;
    emit parameter2Changed(m_parameter2);
}