Pass param via h:link using bean with the same view scope( has a value of null and thus will not be added to the URL)

Question

I have one bean with view scope and want pass parametr between two different pages and on first page before this link I have <p:selectOneMenu/> where I choose test which id should be pass as GET param

<p:selectOneMenu value="#{addQuestion.test}" id="tests"
    converter="#{testConverter}" required="true" requiredMessage="Please, choose test">
    <f:selectItem itemLabel="--Select a test--" itemValue="" />
    <f:selectItems value="#{addQuestion.testList}" var="testItem"
        itemValue="#{testItem}" itemLabel="#{testItem.testName}" />
    <p:ajax process="@this"
        listener="#{addQuestion.getQuestionsBySubject()}"
        update="addingQuestionsTable, testId" />
</p:selectOneMenu>
<h:link value="Add new question" outcome="addQuestion">
    <f:param id="testId" name="testId" value="#{addQuestion.test.testIdentifer.testId}"/>
</h:link>

//in second page

<f:metadata>
    <f:viewParam name="testId"
        value="#{addQuestion.test.testIdentifer.testId}"
        converter="#{testConverter}" required="true" requiredMessage="Invalid page access. Please use a link from within the system."/>
</f:metadata>

And bean

@ManagedBean(name = "addQuestion")
@ViewScoped
public class AddQuestion implements Serializable {
    private Test test;
    //get
    //set
}

But when I try to get value on second page I nothing to get in expression #{addQuestion.test.testIdentifer.testId}" And also in development mode I get

has a value of null and thus will not be added to the URL.

My #{testConverter} is managed bean in view scope.

How I can pass testId in one bean with view scope and why I get this error?

Answer 1

The <f:xxx> tags like <f:param> doesn't generate any HTML and thus have nothing to update in the HTML DOM tree on ajax request. The <h:xxx> components are the ones which generate HTML and are updatable in the HTML DOM tree on ajax request. You need to update the <h:link> component instead of the <f:param> tag. So, move that id from <f:param> to <h:link>.

<h:link id="testId" value="Add new question" outcome="addQuestion">
    <f:param name="testId" value="#{addQuestion.test.testIdentifer.testId}"/>
</h:link>