Dynamic SelectOneListBox failing validation on process - ajax

Question

I have a selectOneListBox and a button
<p:selectOneListbox id="somelistBox" value="#{bean.selectedItem}" styleClass="listBox">
<f:selectItems value="#{bean.list}" var="item" itemValue="#{item}" itemLabel="#{preparer.prepare(item)}"/>
</p:selectOneListbox>
<p:commandButton id="somebutton" process="#(.listBox)" update="#(.listBox)"/>
and a bean
#Component
public void class Bean
{
private List<Item> list;
private Item selectedItem;
public List<Item> getList()
{
return list;
}
public void getSelectedItem()
{
return selectedItem;
}
public void setSelectedItem(Item selectedItem)
{
this.selectedItem = selectedItem;
}
}
However, when I press the button the validation fails on selectOneListBox during the ajax post. From what I've read this can happen when you are trying to set the bound object in the bean with the wrong type of object, however my selectOneListBox contains a list of "Items" and the value is selectedItem which is also an "Item" so I can't see where I'm going wrong.

Answer 1

I think my problem was borne out of a misunderstanding of how browers work. They have no knowledge of java objects, just strings, so attempting to pass the objects back and forwards between browser and server was impossible. Instead I have changed the item value to the id of the item and then had to retrieve this object on the back end with a database call, ie
<p:selectOneListbox id="somelistBox" value="#{bean.selectedItem}" styleClass="listBox">
<f:selectItems value="#{bean.list}" var="item" itemValue="#{item.id}" itemLabel="#{preparer.prepare(item)}"/>
</p:selectOneListbox>
and then some call on the back end to get the object back from the id that is passed by the ajax post (I chose to do this in a Converter).