JSF does not find component ID

Question

I have something like

<p:panelGrid id="tabelaUm">
    <h:form id="formUm" rendered="#{condicao ? true : false}"/>
    <p:commandButton action="#{condicao = false}" update="formUm, formDois"/>
</p:panelGrid>
<p:panelGrid id="tabelaDois">
    <h:form id="formDois" rendered="#{condicao ? false : true}"/>
</p:panelGrid>

When I try to access the page, an exception FacesException is launched:

Cannot find Component with Expression "formDois" referenced from "formUm:j_idt185".

How can I solve this problem?

Answer 1

Because they are in different forms, the CommandButton and the formDois, to Search Expression which you used is not valid.

The Search Expression Framework is the framework that Primefaces uses to locate components in the tree, either through the attribute process or of update.

He accepts some rules, like:

1. @this
2. @form
3. @Parent
4. @all
5. @None

And others...

In addition to some modifiers like ":", which defines the hierarchy.

In your case the rule should be:

update=":formUm, :formDois"

If the CommandButton is inside the formUm then I would be:

update="@form, :formDois"

Putting the ":" at the beginning means it is to start the search from the ViewRoot.

Remembering that his commandButton needs to be inside a form and there can be no form's nested.

Some references:

1. http://www.primefaces.org/showcase/ui/ajax/search.xhtml
2. http://blog.primefaces.org/? p=2740