Creating a dropdown box with no default selection label (Seam JSF controls)

Everybody knows the dropdownbox. You can see it in the image at the left of your screen. It's very easy to create it with Seam:

<h:selectOneMenu value="#{criteria.name}" id="name">
    <s:selectItems var="name"
        value="#{nameManager.getNames()}"
        label="#{messages[nameManager.getKey(name)]}"/>
    <s:convertEnum />
</h:selectOneMenu>

The class NameManager has a method getNames() which returns a a list of enums. The s:convertEnum tag will convert the enum to a text based String. The label attributes is used to translate the name in the correct language (with help of the getKey() method of course, which will return a String).

Now, my problem was that there was a default label (the empty String), and I wanted to be one of the select items to be selected by default.
Easy said, easy done. In your backend, make sure #{criteria.name} is initialized to an enum which holds the default value.

So with this change, one of the select items was selected by default. The problem was: the empty label was STILL there!
After doing some research, I noticed I had to specify the hideNoSelectionLabel : true.

So my code would look like:

<h:selectOneMenu value="#{criteria.name}" id="name">
    <s:selectItems var="name"
        value="#{nameManager.getNames()}"
        label="#{messages[nameManager.getKey(name)]}"
        hideNoSelectionLabel="true"/>
    <s:convertEnum />
</h:selectOneMenu>

... but still, the no selection label was visible :-). The final trick I had to do, was to specify the h:selectOneMenu to required

<h:selectOneMenu value="#{criteria.name}" id="name" required="true">
    <s:selectItems var="name"
        value="#{nameManager.getNames()}"
        label="#{messages[nameManager.getKey(name)]}"
        hideNoSelectionLabel="true"/>
     <s:convertEnum />
</h:selectOneMenu>

Problem solved :-) !