Unable to pass a parameter <apex:param> to the relevant method - salesforce

Question

Lets assume I have a Page code:
<apex:pageBlockTable value="{!allContacts}" var="c" >
<apex:column value="{!c.id}" headervalue="ID"/>
<apex:column value="{!c.FirstName}" headervalue="First Name"/>
<apex:column value="{!c.LastName}" headervalue="Last Name"/>
<apex:column value="{!c.Title}" headervalue="Title"/>
<apex:column value="{!c.Company}" headervalue="Company"/>
<apex:column>
<apex:commandButton action="{!addToRecruits}" value="Recruit">
<apex:param assignTo="{!leadID}" name="leadID" value="{!c.id}"/>
</apex:commandButton>
</apex:column>
</apex:pageBlockTable>
And relevant controller :
public String leadID { get; set; }
public PageReference addToRecruits() {
System.debug('LeadID is: ' + leadID);
List<Lead> potentialCandidate = [SELECT id, FirstName, lastName, Title, Company FROM Lead WHERE id = :leadID];
delete potentialCandidate;
return null;
}
It seems that I can NOT pass leadID to addToRecruits() method. Do you have any idea why is so?
UPDATE:
I could manage to solve it. Instead of querying using SOQL, I approached with this style:
public String leadID { get; set; }
public PageReference addToRecruits() {
Lead candidate=new Lead(id=leadID);
....
}

Answer 1

Looks like the infamous platform bug? where apex:param values are not always send to the controller with apex:commandButton (though they are send with apex:commandLink).
A simple overview of the issue and possible workarounds are summarised by Jeff Douglas here: http://blog.jeffdouglas.com/2010/03/04/passing-parameters-with-a-commandbutton/

Answer 2

Add "rerender" attribute to apex:commandButton and its will start working - Something like
<apex:commandButton rerender="myForm" action="{!addToRecruits}" value="Recruit">

Answer 3

There is one way to pass parameter to controller but it will use commandLink also. I mean we need to use
command link and command button
Eg:
<apex:commandLink action="{!applyNow}" id="applybuttonLink" style="text-decoration:none">
<apex:commandButton value="Apply now"/>
<apex:param name="passId" assignTo="{!passId}" value="{!Vac.id}"/>
</apex:commandLink>
Controller:
public String vacancyId{get;set;}