How to pass parameter to f:ajax in h:inputText? f:param does not work

Question

I need to pass a parameter to the server in my ajax request. Please see the code below. Scope: View Scope

Without f:param

<p:column width="40">
    <h:inputText id="originalCostInputTxt" value="#{articlePromo.costoBruto}" 
        <f:ajax event="change"
            execute="@this" 
            listener="#{promotionDetailManagedBean.onCostoBrutoChange}">
        </f:ajax>
    </h:inputText>
</p:column>

Managed Bean

public final void onCostoBrutoChange(final AjaxBehaviorEvent event) {
    createCostoBrutoOptions(promoArticlesList);
}

In this case, the method onCostoBrutoChange() does gets invoked. But, it does not get invoked when I include f:param. Please see the code below.

With f:param

<p:column width="40">
    <h:inputText id="originalCostInputTxt" value="#{articlePromo.costoBruto}" 
        <f:ajax event="change"
            execute="@this" 
            listener="#{promotionDetailManagedBean.onCostoBrutoChange}">
         <f:param value="#{articlePromo.promocionArticuloId}" name="myId"/> 
        </f:ajax>
    </h:inputText>
</p:column>

Managed Bean

public final void onCostoBrutoChange(final AjaxBehaviorEvent event) {
    createCostoBrutoOptions(promoArticlesList);
    String id = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("myId");
}

Not able to identify whats incorrect in this code. Please guide.

Thanks, Shikha

Answer 1

The <f:param> works in links and buttons only, not in inputs.

If your environment supports EL 2.2, just pass it as method argument instead:

<h:inputText ...>
    <f:ajax listener="#{bean.listener(item.id)}" />
</h:inputText>

public void listener(Long id) {
    // ...
}

You can also just pass the whole item:

<h:inputText ...>
    <f:ajax listener="#{bean.listener(item)}" />
</h:inputText>

public void listener(Item item) {
    // ...
}

If your environment doesn't or can't support EL 2.2, then evaluate EL programmatically instead.

public void listener() {
    FacesContext context = FacesContext.getCurrentInstance();
    Long id = context.getApplication().evaluateExpressionGet(context, "#{item.id}", Long.class);
    // ...
}