dynamic Delegate component and use of DelegateModelGroup in DelegateModel

Mephi

Hello,
i have a simple test qmlproject, where i create a dynamically a delegate for a gridview, this delegate is used in a DelagetModel with groups, but in the delegate the groups are undefined :-(
here is a short example code:

Rectangle {
    id: root
    anchors.fill: parent

    property var trackObjectViewDelegate: Qt.createComponent("DelegateItem.qml", root)

    DelegateModel {
        id: visualModel

        model: ListModel {
            ListElement { name: "blue" }
            ListElement { name: "green" }
            ListElement { name: "red" }
        }

        groups: [
            DelegateModelGroup { name: "selected" }
        ]

        delegate: trackObjectViewDelegate
    }

    GridView {
        id: gridID
        anchors.fill: parent

        model: visualModel

        cellHeight: 300
        cellWidth: 300
    }
}

in the DelegateItem.qml i try to read the selected property like this:

Rectangle {
    id: item
    height: 25
    width: 200
    Text {
        text: {
            var text = "Name: " + name
            if (item.DelegateModel.inSelected)
                text += " (" + item.DelegateModel.selectedIndex + ")"
            return text;
        }
    }
    MouseArea {
        anchors.fill: parent
        onClicked: item.DelegateModel.inSelected = !item.DelegateModel.inSelected
    }
}

It is not working, and i get following error:
TypeError: Cannot read property 'inSelected' of undefined

Does anybody know what to do?
If i not create the delegate dynamically, then it is working perfect, but this is not an option.

p3c0

Hi @Mephi and Welcome,

TypeError: Cannot read property 'inSelected' of undefined

The error says it exactly. The element is indefined and thus cannot access that property. Also I fail to see property named inSelected.

You can either use parent or directly use id of DelegateModel.

Mephi

Hello p3c0,

thanks for your reply, i know that the property inSelected is undefined, thats the intension of my question ;-) , but why it is undefined?

it has to be defined, because it is working if i not create the delegate dynamically.

inSelected property is generated automatically
http://doc.qt.io/qt-5/qml-qtqml-models-delegatemodel.html#groups-prop

p3c0

@Mephi Hmm, sorry for that. I wasn't aware of it as i have never used it before. So digging in it seems that the attached properties of DelegateModel doesn't seem to work if the delegate is in separate file. Could be a bug I suppose. You can try reporting it here.