first item in a combobox

Vaadin 6 / 7 / 8 Framework UI
1

When I choose the first row in a combobox it appears as a choosen value like any other item. I mean that empty row before the first item that I have added.
Question:
Is there any possibility to utilize that first item (empty row) of a combobox in a valueChange listener?

Tapani
11139.png

2

I think ComboBox.setNullSelectionAllowed(boolean) is what you’re looking for.

3

Jouni,
I did not have enough information in my question. There are two different comboboxes in Vaadin. One can be created by a Bean like in my case:

setItemDataSource(new BeanItem(valikotDataModel));

Then I populate combos:

for (int i = 1; i < order.length; i++) {
			comboItems = hakuLauseVaadin.alkuarvotComboboxiin(order[i]
);
			replaceWithSelect(order[i]
, comboItems, comboItems)
					.setNewItemsAllowed(false);
			getField(order[i]
).addListener(valintaListener);
		}

The other like this example: http://vaadin.com/tutorial/-/page/tuning.combobox.html

private final ComboBox cities = new ComboBox("City");
...
PersonContainer ds = app.getDataSource();
 for (Iterator<Person> it = ds.getItemIds().iterator(); it.hasNext();) {
     String city = (it.next()).getCity();
     cities.addItem(city);
 }

After your suggestion of “ComboBox.setNullSelectionAllowed(boolean)” I found that the first row in my bomboboxes is null.
Thanks