how to reload p:dataGrid programmatically? - jsf

Question

I have a datagrid with subscribe and unsubscribe option so the user can subscribe and unsubscribe and vise verse.
now I want to reload the datagrid after subscription or unsubscription
I load the data of the grid like that
#PostConstruct
public void init() {
packages = packagehelper.getAllPackages();
getCurrentUserSubscritions();
}
and here is the xhtml file
<h:form id="form">
<p:growl id="growl" showDetail="true" sticky="false" life="8000" />
<p:dataGrid var="package" value="#{packageView.packages}" columns="3"
>
<p:column>
<f:facet name="header">
Cars for Sale
</f:facet>
<p:panel header="#{package.id}" style="text-align:center">
<h:panelGrid columns="2" style="width:100%">
<p:graphicImage width="100px" name="images/#{package.imageurl}"/>
<h:outputText value="#{package.name}" />
<h:outputText value="#{package.value} EGP for #{package.duration} Days " />
<h:outputText value="#{package.description}" />
<p:commandButton ajax="true" update=":pack" value="Subscribe" rendered="#{!packageView.IsPackageActive(package.id)}" action="#{packageView.Subscribe()}" >
<f:setPropertyActionListener value="#{package.id}" target="#{packageView.packageID}" />
<f:setPropertyActionListener value="#{package.duration}" target="#{packageView.packageDuration}" />
</p:commandButton>
<p:commandButton action="#{packageView.Unsubscribe}" update=":pack" ajax="true" value="Cancel" rendered="#{packageView.UserHasPackage(package.id) and packageView.IsPackageActive(package.id) }">
<f:setPropertyActionListener value="#{package.id}" target="#{packageView.packageID}" />
<f:setPropertyActionListener value="#{package.duration}" target="#{packageView.packageDuration}" />
</p:commandButton>
</h:panelGrid>
</p:panel>
</p:column>
</p:dataGrid>
</h:form>

Answer 1

When an suscribe or unsuscribe action is completed, you should actualize the DataGrid trough its ID, it is, set an ID to the DataGrid and put such id in the update property of the buttons.
For example:
<p:dataGrid id="datalist" .../>
<p:commandButton action="#{packageView.Unsubscribe}" update="datalist" .../>
And when the action of the button is submited set the packages in null, so when the update action of the DataGrid update the packages they should be called again of the persistence or data base.
It is important to consider how to reference the elements in update property. You can see this answer