To display validation message in primefaces dialog from managed bean - jsf-2

Question

i am trying to display the message of the outcome of a validation done in managed bean in the dialog but it is not getting displayed in the dialog on submit of the form.
Please help me in fixing this
My JSF page snippet with dialog
<p:dialog header="Add LPC" id="lpcDlg" widgetVar="dlg" rendered="true"
appendToBody="true" resizable="true" modal="true" height="320px"
width="38%">
<h:form id="addLpc">
<div align="center" style="margin-bottom: 1px; padding-bottom: 1px;">
<h:outputLabel value="Add New LPC"
style="font-color:#000000;font-weight:bold;font-size:24px;padding-bottom:1px;"></h:outputLabel>
</div>
<div align="center">
<p:messages id="lpcDlgMsg" showDetail="false" autoUpdate="true"
closable="true" />
<p:messages id="lpcDlgMsg2" for="lpcDlgMessage" showDetail="false"
autoUpdate="true" closable="true" />
<h:panelGrid id="addLpcForm" columns="2" appendToBody="true">
<h:outputText value="LPC ID" />
<p:inputText id="lpcId" value="#{lpcBean.lpcId}" required="true"
requiredMessage="LPC ID is required">
<f:ajax event="blur" render="lpcDlgMsg" />
</p:inputText>
<h:outputText value="First Name" />
<p:inputText id="firstName" value="#{lpcBean.firstName}" />
.
.
.
.
</h:panelGrid>
</div>
<div align="center">
<p:commandButton id="submitButton" value="Submit" ajax="true"
update=":lpcForm:lpcDataTable,addLpc"
action="#{lpcBean.formSubmit}" oncomplete="dlg.hide()" />
<p:commandButton id="cancelButton" value="Cancel"
onclick="dlg.hide()" />
</div>
</h:form>
</p:dialog>
message with id lpcDlgMsg2 is the message i am trying to display on submit.The other message is getting displayed correct on blur.
Snippet of the method that is called on submit
public void formSubmit()
{
if(resultSet.next())
{
int lpcIdCount=rs.getInt("lpcCount");
if(lpcIdCount!=0)
{
FacesContext.getCurrentInstance().addMessage("lpcDlgMessage", new FacesMessage(FacesMessage.SEVERITY_ERROR," ", "Duplicate LPCID"));
System.out.println("after display");
}
else
{
.
.
.
.
}
}
}
}

Answer 1

Here is my suggestion:
<p:dialog header="Add LPC" id="lpcDlg" widgetVar="dlg" rendered="true"
appendToBody="true" resizable="true" modal="true" height="320px"
width="38%">
<h:form id="addLpc">
<div align="center">
<p:messages id="lpcDlgMsg" showDetail="false" autoUpdate="true"
closable="true" />
<h:panelGrid id="addLpcForm" columns="2" >
<h:outputText value="LPC ID" />
<p:inputText id="lpcId" required="true" />
<h:outputText value="First Name" />
<p:inputText id="firstName" required="true" />
</h:panelGrid>
</div>
<div align="center">
<p:commandButton id="submitButton" value="Submit"
oncomplete="if (!args.validationFailed){dlg.hide();}" />
<p:commandButton id="cancelButton" value="Cancel"
onclick="dlg.hide()" />
</div>
</h:form>
</p:dialog>
Note that I've simplified your code in order to avoid using a managedbean.
If you want your managed bean to perform the validation, use RequestContext to conditionally execute the code that will close the dialog and remove the oncomplete from Submit button.
if (success) {
RequestContext.getCurrentInstance().execute("dlg.hide()");
}else{
//show all the messages you need here
}

Answer 2

You have to add this javascript first inside head tag
function handleComplete(xhr, status, args) {
if (!args.validationFailed) {
dlg.hide();
} else {
}
}
More changes are
<p:commandButton id="submitButton" value="Submit" ajax="true"
update=":lpcForm:lpcDataTable,addLpc :lpcDlgMsg2"
actionListener="#{lpcBean.formSubmit}" oncomplete="handleComplete(xhr, status, args)" />
action to actionListener because action has String return type.
This will work fine.