How to initiate a binding property updating by change another property from javascript?

[DenisFromNN]

Hello

I have some QML sample which sets a source of image and automatically changes its width and I want the width of parent has been also updated without explicit intervention

import QtQuick 2.3
import QtQuick.Controls 1.3

Item {
    width: 300; height: 300
    Item
    {
        id: item
        width: element.width
        height: element.height

        Column
        {
            id: element
            Image
            {
                id: image
            }
            Label
            {
                id: label
                text: "K"
            }
        }

        Component.onCompleted:
        {
            console.log ("Width item: " + item.width + " element: " + element.width + " image: " + image.width + " label: " + label.width)
            image.source = "img.bmp"
            console.log ("Width item: " + item.width + " element: " + element.width + " image: " + image.width + " label: " + label.width)
        }
    }
}

Console output shows that width of image is updated, but width of column (named "element") don't. How to do it automatically updated?

[xargs1]

This post is deleted!

[chrisadams]

You should be able to do this declaratively, by declaring either:

width: image.width

OR

width: childrenRect.width

for the "element" column.

Note that this will "bind" the values. Binding is automatic in QML declarations. If you wish to bind from an imperative statement (ie, from within a JavaScript function) you can use:

width = Qt.binding(function() { image.width });

Hope this helps!