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k2sfdevk2sfdev 

Controller function fired twice on every postback

Who can explain this?

 

visual page:

 

<apex:page controller="TestBinding" >
<apex:form>
<apex:pageBlock title="Test Binding">
<apex:pageblockButtons>
<apex:commandButton value="Login"/>
</apex:pageblockButtons>
<apex:pageblockTable value="{!Accounts}" var ="a">
</apex:pageblockTable>
</apex:pageBlock>
</apex:form>
</apex:page>
 Controller
 
 
public class TestBinding {   
 public List<Account> getAccounts(){       
  List<Account> li = new List<Account>();       
  return li;   
 }
}
 Apex log:
 
 
10:20:11 DEBUG - 
***Begining Page Log for /apex/TestBinding 20090901152010.938:
External entry point: returning LIST:SOBJECT:Account from method public LIST:SOBJECT:Account getAccounts() in 0 ms 20090901152010.938:
External entry point: returning LIST:SOBJECT:Account from method public LIST:SOBJECT:Account getAccounts() in 0 ms 
Cumulative profiling information: No profiling information for SOQL operations. 
No profiling information for SOSL operations. 
No profiling information for DML operations. 1 most expensive method invocations: Class.TestBinding: line 2, column 25: 
public LIST:SOBJECT:Account getAccounts(): executed 2 times in 0 ms  
***Ending Page Log for /apex/TestBinding?core.apexpages.devmode.url=1 
 Any idea to avoid calling getAccounts twice?
 
 
 
 
 
Message Edited by k2sfdev on  09-01-2009 08:35 AM


k2sfdevk2sfdev
I guess one is init the page, the other is rerender the page.
 
Is there something like 
 
 
 if ( Apex.PagesPostbackBy('controlID')) then....
 
 
?
 
Thank you  


JimRaeJimRae
You could try not rendering the form on init, and then updating the render, and refresh the pageblocktable on the submit of your button.
 
 
 
<apex:page controller="TestBinding" >

<apex:form>

<apex:pageBlock title="Test Binding">

<apex:pageblockButtons>

<apex:commandButton value="Login" rerender="bTable" />

</apex:pageblockButtons>

<apex:pageblockTable value="{!Accounts}" var ="a" rendered="{!showblock}" id="bTable">

</apex:pageblockTable>

</apex:pageBlock>

</apex:form>

</apex:page>
 
public class TestBinding {
public boolean showblock=false;
public List<Account> getAccounts(){

List<Account> li = new List<Account>();
showblock=true;
return li;

}

}
 
 
 
 
 


k2sfdevk2sfdev
Hi Jim,
 
Thankyou for your reply,
 
 
 getAccounts will not be called when page is loading. ( my version it will be fired once.)
 
 But it's still fired twice when you click commandButton.
 
 
 

Message Edited by k2sfdev on  09-01-2009 01:57 PM


HarmpieHarmpie
It is not executed twice. If you have a good look at the debug log you will see that the line marked in red is not an execution, but a 'summary' line, telling you the the getAccounts method executed in xx ms


JimRaeJimRae
Actually, it does say executed 2 times in 0 MS


HarmpieHarmpie
You're right, misread the post/log.
 
Could you post your entire apex code? 


k2sfdevk2sfdev
Hi Harmpie & Jim,
 
My code are actually kind of complicated. I just simplified it as my first post to proof the concept.
If you add counter,you will see it more clearly.
 
 
I tuned my code many times, finally I realized it's force.com framework's problem and no official 
safe methods to avoid it. 
 
 
Thank you