function cntrlSearchSuggestion_onClientItemsRequesting(sender, eventArgs) {
    if (eventArgs.get_text().length < 2) {
        eventArgs.set_cancel(true);
        sender.hideDropDown();
        sender.get_items().clear();
    }
}

function cntrlSearchSuggestion_onClientItemsRequested(sender, eventArgs) {
    if (sender.get_items().get_count() == 0) {
        sender.hideDropDown();
    } else {
        sender.showDropDown();
    }
}

function cntrlSearchSuggestion_onClientDropDownOpening(sender, eventArgs) {
    if (sender.get_items().get_count() == 0) {
        eventArgs.set_cancel(true);
    }
}