I have a method to get the param value :

public PageReference facultyid() {
  public String fid{get;set;}    
  System.debug('facultyId: ' + fid);  
  return null;

My page calls and sets this function as below:

<apex:pageBlockTable value="{!faculties}" var="f"  id="fblock" rendered="{!faculities.size!=null}">
  <apex:column >
    <apex:actionregion >   
      <apex:outputpanel id="plusimage">
        <apex:image url="{!$Resource.Plus_Image}" onclick="switchMenu('{!$Component.inlinetablesec}','{!$Component.minusimage}','{!$Component.plusimage}')" title="Expand - Faculties"> 
          <apex:actionsupport event="onclick" action="{!facultyid}">
            <apex:param name="facultyid"  value="{!f.id}" assignTo="{!fid}" />

So it should pass the "fid" value immediately, but it is not happening... its showing me null value in debug logs why is it so? am i doing something wrong here, please help me to get the value of fid to controller, i can't use action function as its inside the output panel between tables, so please suggest me. Thanks in advance for the help.

5 Answers 5


Param will be passed on post of form to server.

In your action support you don't have any rerender attribute. Add a rerender attribute and give id plusimage.

One more thing to note is apex:param behaves differently when passing id value with string literal in name attribute.

If you change this

<apex:param name="facultyid" value="{!f.id}" assignTo="{!fid}"/>


<apex:param name=" {!f.id} " value="{!f.id}" assignTo="{!fid}"/>

it works. Its not documented anywhere but usually works for me.

Hope it helps.

  • When i add Rerender = plusimage or my pagblock id - its not expanding -means no action is performed now at all...
    – sfdev
    Commented Jul 21, 2015 at 8:18
  • Then you should rerender whole form. Commented Jul 21, 2015 at 8:28
  • still it is coming as null;
    – sfdev
    Commented Jul 21, 2015 at 8:38
  • Updated my answer to address this issue. Take a look and let me know if it worked. Commented Jul 21, 2015 at 8:54

try using Command button.

<apex:commandButton action="{!removeCon}" id="remov" image="{!URLFOR($Resource.minus_icon1)}" style=" height:25px;  width:25px;"reRender="pb2">
<apex:param name="selectedIndex" value="{!Wap.index}" /> 
  • i don't want commandbutton on it , if i use commanbutton or commandlink , its working fine , but i dont want to use command button , its just expand all image
    – sfdev
    Commented Jul 21, 2015 at 10:52
  • i tried with commandbutton or commandlink for apex param , and its not working
    – sfdev
    Commented Jul 22, 2015 at 9:05

Shouldn't fid be declared with its get & set before the method? Otherwise, the method should work with the local values.

  • i have declared it before the method only but as i can't post my all lines of code over here , just added get set is declared to show.
    – sfdev
    Commented Jul 22, 2015 at 8:46

I don't know whats happening with apex param for apex support , So i just used below code to complete my requirement using action function

<apex:actionFunction name="for faculty" action="{!facultyid}" rerender="myoutputpanel" > <apex:param name="fid" value="{0}" /></apex:actionFunction>

I had the same problem when using param to pass value to apex code. Below code solve my problem. //apex code

public String fid{
        fid = value;
public PageReference facultyid(){
    system.debug('fid = ' = fid);

//vf page

<apex:param name="fid" value="{!f.id}" assingTo="{!fid}"/>

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