......

model: ListModel {
        id: cbItems
        ListElement { text: ""; iconSource: "image1"}
        ListElement { text: ""; iconSource: "image2"}
    }

__dropDownStyle: MenuStyle {
            id: dropDownMenuStyle
            frame: dropDownMenuStyleFrame
//            __menuItemType: "comboboxitem"
            itemDelegate.label: Rectangle {
                width: root.width - 50
                height: root.height
                color: "transparent"
                Image {
                    id: operatorPic
                    width: height
                    height: operatorPictureHeight
                    anchors {
                        left: parent.left
                        leftMargin: 2
                        verticalCenter: parent.verticalCenter
                    }
                    source: operatorPic.height === 0 ? "" : styleData.iconSource
                }
                ITextLabel {
                    width: parent.width - operatorPic.width - 2 - 5
                    height: parent.height
                    fontSize: 20
                    fontColor: styleData.selected ? "white" : "black"
                    text: styleData.text
                    wrapMode: Text.WrapAtWordBoundaryOrAnywhere
                    horizontalAlignment: Text.AlignLeft
                    anchors.left: operatorPic.right
                    anchors.leftMargin: 5
                }
            }

            itemDelegate.background: Rectangle {
                z: 1
                opacity: 0.5
                height: root.height
                color: styleData.selected ? "#0098DF" : "transparent"
            }
    }

I know source: operatorPic.height === 0 ? "" : styleData.iconSource does not work but I have no idea how to deal with it.

Does anybody tell me how to do it?
Thanks.