reRender & rendered attributes in Salesforce

This example gives you to understand how to use reRender a field if other checkbox filed is true.

What is rendered Attribute? It is a Boolean value weather the component is rendered on visualforce page. If it is not specified, default value is always true.

What is reRender Attribute? This attribute is useful to render some other visualforce component based Boolean value.

See the below example to understand usage of reRender & rendered attributes.

Vehicle__c is a custom objected I created on my developer box. “Is_insured__c & Insured_Ammount__c” are custom fields on this custom object. “Name” is the standard name field on this custom object.

Apex Class:

public class VehicleRegisrationController {

public Vehicle__c V1 { get; set; }
public VehicleRegisrationController()
{
V1 = new Vehicle__c();
}

public void saveMethod() {
if(V1.Is_insured__c==true)
{
insert V1;
}
}
}

Visualforce Page:

<apex:page controller="VehicleRegisrationController">

<apex:form id="formId">

<apex:pageBlock >

<apex:pageBlockTable value="{!V1}" var="v">

<apex:column headerValue="Vehicle Name">

<apex:inputField value="{!V1.Name}"/>

</apex:column>

<apex:column headerValue="Is insured">

<apex:inputField value="{!V1.Is_insured__c}">

<apex:actionSupport event="onclick" reRender="formId"/>

</apex:inputField>

</apex:column>

<apex:column headerValue="Amount">

<apex:inputField value="{!V1.Insured_Amount__c}" rendered="{!V1.Is_insured__c==true}"/>

</apex:column>

</apex:pageBlockTable>

</apex:pageBlock>

<apex:commandButton value="Save" action="{!saveMethod}"/>

</apex:form>

</apex:page>

This is a simple example to use reRender & rendered attributes. You can leave a comment if you have any doubts.