Dynamic ChartView updating

[Milosz]

In my program data for chart are producing in c++ and the QML function is called like this

QMetaObject::invokeMethod(view.rootObject(), "readValues", Qt::DirectConnection,
            Q_ARG(QVariant, QVariant::fromValue(list)));

then data series are appended in readValues function

Item{
    id: chart
    ChartView {
        id: chartView
        width: parent.width
        height: parent.height
        theme: ChartView.ChartThemeLight
        antialiasing: true
        legend.visible: false

        ValueAxis {
            id: axisX
            titleText: "D   N   I"
            labelsFont: Qt.font({pointSize: 12, bold: true})
            min: 0
            max: 200
            tickCount: 21
            labelFormat: "%.0f"
        }

        ValueAxis {
            id: axisY
            labelsFont: Qt.font({pointSize: 12, bold: true})
            min: 0
            max: 14000
            tickCount: 8
            labelFormat: "%.0f"
        }

        LineSeries {
            id: infectedSeries
            axisX: axisX
            axisY: axisY
            color: "blue"
            width: 4
        }
    }

    function readValues(collection)
    {
        for (var i = 0; i < collection.length; i++)
        {
            infectedSeries.append(i, collection[i]);
            console.log("Array item:   " + i + "   val  " + collection[i]);
        }
        // chartView.update();
    }
}

There is no effect on chart. It is strange because on the console logs are printed properly

Thank you in advance