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heuyeheuye 

variable can't be changed after asignTo?

below is all my code.when i click the commandButton,the pageBlockName doesn't change,why?

use the component in a page:

 

<c:test_updateAttribute blockName="set in page" />

 

component:

 

 

<apex:component controller="test_sample" access="global">
<apex:attribute name="blockName"
    type="String"
    required="true"
    access="global"
    assignTo="{!pageBlockName}" 
    description="The blockName." />

<apex:pageBlock title="{!pageBlockName}" id="resultTable">
<apex:commandButton value="change blockName" action="{!changeName}" reRender="resultTable"/>
</apex:pageBlock>   
</apex:component>

 

component controller:

global with sharing class test_sample{
    public String pageBlockName {get; set;}
   
    public void changeName(){
        pageBlockName = '456';
    }

}

 

 

 

 

 

bob_buzzardbob_buzzard

This is because primitive values (e.g. Strings) are passed by value to components not by reference, so effectively the component takes a copy of the String.

 

Oddly enough I wrote a blog post about this very subject over the weekend and have just published it:

 

http://bobbuzzard.blogspot.com/2011/05/updating-attributes-in-component.html