dataExporter cannot be rendered because of form needing - pdf

Question

I am trying to add dataExporter component to my table.
First I had {Exporters} beside pagination facet , then after a lot of tries I got this error in the console
HTML nesting warning on closing changes: element update not explicitly closed
I solved it also but now there is nothing appears in the Exporter facet. I googled it and found that I need a form in my page because of this commandlink submit a form , so it needs a form.
My Question here is how to apply this example in my project.
Here is my code.
<ui:composition template="/template.xhtml">
<ui:define name="title">
<h:outputText value="#{bundle.ViewLfmTitle}"></h:outputText>
</ui:define>
<ui:define name="body">
<h:panelGroup id="messagePanel" layout="block">
<h:messages errorStyle="color: red" infoStyle="color: green"
layout="table" />
</h:panelGroup>
<p:dialog header="Add Task" widgetVar="dlg" position="center center"
onShow="PF('dlg').initPosition()" modal="true" closeOnEscape="true"
resizable="false">
<h:form>
<h:panelGrid columns="2">
<p:outputLabel value="#{bundle.CreateTaskLabel_name}" for="name" />
<p:inputText id="name"
value="#{ViewLfmJpaController.newTaskDTO.name}"
title="#{bundle.CreateTaskTitle_name}" />
<p:outputLabel value="#{bundle.CreateTaskLabel_durationPerMonth}"
for="durationPerMonth" />
<p:inputText id="durationPerMonth"
value="#{ViewLfmJpaController.newTaskDTO.duration}"
title="#{bundle.CreateTaskTitle_durationPerMonth}" />
<p:outputLabel value="#{bundle.CreateTaskLabel_startDate}"
for="startDate" />
<p:calendar id="startDate"
value="#{ViewLfmJpaController.newTaskDTO.startDate}"
title="#{bundle.CreateTaskTitle_startDate}" pattern="d MMM yyyy"
effect="fold">
<f:convertDateTime pattern="d MMM yyyy" />
</p:calendar>
<p:outputLabel value="#{bundle.CreateTaskLabel_endDate}"
for="endDate" />
<p:calendar id="endDate"
value="#{ViewLfmJpaController.newTaskDTO.endDate}"
title="#{bundle.CreateTaskTitle_endDate}" pattern="d MMM yyyy"
effect="fold">
<f:convertDateTime pattern="d MMM yyyy" />
</p:calendar>
<f:facet name="footer">
<p:commandButton value="Add"
actionListener="#{ViewLfmJpaController.addTask}" update="Matrix"
oncomplete="PF('dlg').hide()" />
</f:facet>
</h:panelGrid>
</h:form>
</p:dialog>
<p:dataTable id="Matrix" resizableColumns="true" scrollable="true"
scrollHeight="80%"
value="#{ViewLfmJpaController.selected.tasksDtoCollection}"
paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {Exporters}"
var="item" resizeMode="expand" paginator="true" rows="10"
style="margin-bottom:20px">
<f:facet name="header">
Logical Framewrok Matrix
</f:facet>
<f:facet name="{Exporters}">
<p:commandLink>
<p:graphicImage name="../resources/images/pdf.jpg" width="24" />
<p:dataExporter type="pdf" target="Matrix" fileName="lfm" />
</p:commandLink>
</f:facet>
<p:column headerText="Index" colspan="1">
<c:forEach var="i" begin="1" end="#{ViewLfmJpaController.listSize}">
<p:outputLabel value="#{i}"></p:outputLabel>
</c:forEach>
</p:column>
<p:column headerText="Task Title">
<p:outputLabel value="#{item.name}"></p:outputLabel>
</p:column>
<p:column headerText="Start Date" colspan="3">
<p:outputLabel value="#{item.formatedStartDate}"></p:outputLabel>
</p:column>
<p:column headerText="End Date" colspan="3">
<p:outputLabel value="#{item.formatedEndDate}"></p:outputLabel>
</p:column>
<c:forEach var="i" begin="1"
end="#{ViewLfmJpaController.numberOfMonths}">
<p:column headerText="m ${i}" colspan="1"></p:column>
</c:forEach>
<p:column headerText="Exptected Outcomes" colspan="4">
<ui:repeat value="#{item.tasksExpectedOutcomesCollection}" var="teo">
<li><h:outputText value="#{teo.expectation}">
</h:outputText></li>
</ui:repeat>
</p:column>
</p:dataTable>
<p:commandButton value="Add Task" oncomplete="PF('dlg').show()"></p:commandButton>
</ui:define>
</ui:composition>

Answer 1

I FOUND THE SOLUTION BY MYSELF.
First : You have to know that you cannot make nested forms in your page.
Second : you have to know that to submit <p:dialog> </p:dialog> or to use <h:commandLink> </h:commandLink> you need to use form.
So I had removed the form in the dialog component and add a general component contains dialog and dataTable together