Rendered is to display one component or a group of components with condition from DOM . Rerender is something to refresh some component with some action . You can add more then one component Id to refresh on Rerender .
Please let me know any issue ,If it helps you understand the concepts select beat answer to help others.
Rendered - It is same as you are displaying a block based on some condition...if that condition will become true then only that block will be visible . example:
Rerender - It means a particular block or section you are refershing....
example:
You have one block where you are showing the contacts related to account and then onclick of add button you have added one more contact to account...so instead of refershing and reloading the entire page, you can simply refersh the section which shows the contact related to account..
Rendered is to display one component or a group of components with condition from DOM .
Rerender is something to refresh some component with some action .
You can add more then one component Id to refresh on Rerender .
Please let me know any issue ,If it helps you understand the concepts select beat answer to help others.
Rendered - It is same as you are displaying a block based on some condition...if that condition will become true then only that block will be visible .
example:
<apex:outputpanel rendered ="{If(lstAcc.size >0 , true, false)}">
</apex:outputpanel>
Rerender - It means a particular block or section you are refershing....
example:
You have one block where you are showing the contacts related to account and then onclick of add button you have added one more contact to account...so instead of refershing and reloading the entire page, you can simply refersh the section which shows the contact related to account..
<apex:outputpanel id="dummyId">
</apex:outputpanel>
<apex:commandbutton onclick="someaction" action="{!method}" rerender="dummyId" />
In above example on clik of button we are refershing the panel which has id as dummyId..
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Thanks,
Sandeep
Salesforce Certified Developer