Changing model root in a Package of a DelegateModel

[Royal Bissell]

I am working with hierarchical data in Qabstractitemmodel in QML within a Delegate model and Package component in order to allow me to display a list and then details on an item.

    DelegateModel {
        id: delegateModel
        model: myModel
        delegate: Package {
            GridDelegate {
                onClicked: {
                    details.root = gridview.model.modelIndex(index)
                }
                Package.name: 'grid'
            }
            DetailsDelegate {
                Package.name: 'details'
            }
        }
    }

The issue is that now that the delegate is in a Package component gridview.model is now a QqmlPartsModel and I get Property 'modelIndex' of object QQmlPartsModel(0xd75fa0) is not a function

Qt example: http://doc.qt.io/qt-5/qml-qtqml-models-delegatemodel.html#rootIndex-prop

Is there another way I should be going about this.