I'm stuck on dynamic panel - primefaces

Question

I met a problem for two days. nowhere I advance
my problem is to make a dynamic content in a panel according to the selected element in the list p: selectOneMenu
<h:outputLabel value="Categorie :" />
<p:selectOneMenu value="#{composantbean.selectedCategoryId}" required="true" >
<f:selectItem itemLabel="Select categorie" itemValue="" />
<f:selectItems value="#{composantbean.listcat}" var="cat" itemValue="#{cat.nomCat}" itemLabel="#{cat.nomCat}" />
<p:ajax update="panl" event="change" listener="#{composantbean.catListener()}"/>
</p:selectOneMenu>
<p:panel id="panl" header ="Caracteristique selon la categorie" toggleable="true" rendered="true" >
<h:panelGrid id="panlecart" columns="2" cellpadding="5" rendered="true">
<c:forEach items="#{composantbean.categorie.proprietes}" var="var">
<h:outputText value="#{var.nomProp}"/>
<h:inputText value="" />
</c:forEach>
</h:panelGrid>
</p:panel>
content appears this is true but unfortunately it is not synchronized is displayed shift
but if I use another <p: selectOneMenu id = "panel" content is displayed and synchronized
Haw can I fixe my prblem .Please and thank you in advance

Answer 1

As Lucas said, it is a bad idea using c:foreach (and all kind of JSTL) in JSF, especially with ajax.
Here are references you should read, to know more about JSTL in JSF:
JSTL in JSF2 Facelets... makes sense?
https://rogerkeays.com/jsf-c-foreach-vs-ui-repeat
Using ui:repeat in h:panelGrid is not recommended also. You may read the discussion here.
So, IMHO, you should try another approach, such as using dataTable, as stated in above link.
Or, you could use html's table tag (<table>) as replacement of h:panelGrid, with html's tr and td tag inside ui:repeat. For example:
<h:outputLabel value="Categorie :" />
<p:selectOneMenu value="#{composantbean.selectedCategoryId}" required="true" >
<f:selectItem itemLabel="Select categorie" itemValue="" />
<f:selectItems value="#{composantbean.listcat}" var="cat" itemValue="#{cat.nomCat}" itemLabel="#{cat.nomCat}" />
<p:ajax update="panl" event="change" listener="#{composantbean.catListener()}"/>
</p:selectOneMenu>
<p:panel id="panl" header ="Caracteristique selon la categorie" toggleable="true" rendered="true" >
<table>
<ui:repeat value="#{composantbean.categorie.proprietes}" var="var">
<tr>
<td><h:outputText value="#{var.nomProp}" /></td>
<td><h:inputText value="" /></td>
</tr>
</ui:repeat>
</table>
</p:panel>