Example 2

import QtQuick 2.5
import QtQuick.Window 2.2
import QtQuick.Controls 1.4

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

    ComboBox {
        focus: true
        activeFocusOnPress: true
        model: 2
        Keys.onPressed: { console.log("Pressed", event); event.accepted = true }
        Keys.onUpPressed: { console.log("Up", event); event.accepted = true }
        Keys.onDownPressed: { console.log("Down", event); event.accepted = true }
    }
}