<apex: pageMessages> Component in Visualforce Page

The <apex:pageMessages> is another important component that is similar to the <apex: pageMessage> that is also used for displaying all the success, error, and warning messages of all the components that are presented using SF styling on the current page.

We use the <apex:pageMessages> component when we need to get user input for a controller method that doesn't correspond to the field on a sObject.

Just like the <apex: pageMessage> component, the <apex: pageMessages> component also have some attributes which are used when this component is used on the page. These attributes are as follows:

1. id

The id attribute is of type string, i.e., a unique identifier used for allowing the component to be referenced by other components on the page.

Syntax:

2. escape

The escape attribute is of type Boolean that is used for specifying whether the sensitive HTML and XML characters should be escaped in the HTML output generated by the component or not.

Syntax:

3. rendered

The rendered attribute is of type Boolean that is used for specifying whether the component is rendered on the page or not. By default, its value is set to true.

Syntax:

4. showDetail

The showDetail attribute is of type boolean that is used for identifying whether to display the detail portion of the messages or not. By default, its value is set to false.

Syntax:

Let's take examples to understand how we can use the <apex: pageMessages> component in the VF page:

ApexPageMessagesExample1.vfp

<apex:page standardController="Account" recordSetVar="accounts" tabStyle="Account" sidebar="false">
    <apex:pageMessage severity="info" detail="Enter an alphabetic character for the Annual Revenue, then click Save to see what happens." strength="1"/>
    <apex:form >
        <apex:pageBlock >
            <apex:pageMessages />
            <apex:pageBlockButtons >
                <apex:commandButton value= "Save" action= "{!save}"/>
            </apex:pageBlockButtons>
            <apex:pageBlockTable value= "{!accounts}" var= "acc">
                <apex:column value= "{!acc.Name}"/>
                <apex:column value= "{!acc.Rating}"/>
                <apex:column value= "{!acc.Type}"/>
                <apex:column headerValue= "Annual Revenue">
                    <apex:inputField value= "{!acc.AnnualRevenue}"/>
                </apex:column>
            </apex:pageBlockTable>
        </apex:pageBlock>
    </apex:form>
</apex:page>

Output

apex: pageMessages component in Visualforce Page

Let's take another example, in which we set the message detail from the controller class and show it on VF page.

ApexPageMessagesExample2.vfp

<apex:page Controller="PageMessageController" showHeader="false" sidebar="false" title="PageMessages Example">
    <apex:form >
        <apex:pageBlock >
            <apex:pageMessages />
            <apex:pageBlockButtons >
                <apex:commandButton value="Save" action="{!saveRecord}"/>
            </apex:pageBlockButtons>
            <apex:pageBlockSection>
            	<apex:outputText value="{!acc.Name}"></apex:outputText>
                <apex:outputText value="{!acc.ParentId}"></apex:outputText>
                <apex:outputText value="{!acc.Type}"></apex:outputText>
                <apex:outputText value="{!acc.Phone}"></apex:outputText>
                <apex:inputText value="{!acc.Rating}"></apex:inputText>
                <apex:outputText value="{!acc.AnnualRevenue}"></apex:outputText>
            </apex:pageBlockSection>
        </apex:pageBlock>
    </apex:form>
</apex:page>

PageMessageController.apxc

public class PageMessageController {
	String recId;
    public Account acc {get;set;}
    public PageMessageController(){
        acc = new Account();
        ApexPages.addmessage(new ApexPages.message(ApexPages.severity.info, 'Enter an alphabetic character for the Annual Revenue, then click Save to see what happens.'));
        recId = system.currentPageReference().GetParameters().get('Id');
        system.debug('Id ==>'+recId);
        
        acc = [Select Id, Name, Type, AnnualRevenue, rating, ParentId, Phone From Account Where Id =: recId];
    }
    public void saveRecord(){
        if(acc.Rating == 'Hot'){
            ApexPages.addmessage(new ApexPages.message(ApexPages.severity.Confirm, 'Rating is Hot.'));
        }else if(acc.Rating == 'Cold'){
            ApexPages.addmessage(new ApexPages.message(ApexPages.severity.warning, 'Rating is Cold.'));
        }else if(acc.Rating == 'Warm'){
            ApexPages.addmessage(new ApexPages.message(ApexPages.severity.error, 'Rating is Warm.'));
        }   
    }   
}

Output