Pass value to controller from Visualforce

Question

I know there are other questions similar to this but I could not figure out a way to solve my issue. In my Visualforce page, I have a repeater - I need to call the controller method to get data from another object using ID from the repeater object.

Visualforce:

  <apex:repeat var="a" value="{!articles}">            
        <!-- this is how I am setting the ArticleId variable in apex ---NOT WORKING -->
        <apex:param name="ArticleId" value="{!(a.Article_Id__c)}" assignTo="{!ArticleId}"/>          

        <!setFaqAnswer>  <!-- Calling the method -->
        <div class="divQuestion" "> {!a.Title__c} </div>
        <div class="divSummary" > {!a.Summary__c} </div>
        <div  class="divAnswer" > {!faq.Answer__c} </div>  <!--   <-- Using the faq object here -->
  </apex:repeat>

Controller:

public FAQ faq {get;private set;}

public Id ArticleId {
    get; set;
}

public void setFaqAnswer {
    get {
        try {
            faq = [select Answer__c, Links__c from FAQ__kav where KnowledgeArticleId = :ArticleId and IsVisibleInPkb = true];
        }
        catch (QueryException qe) {
            System.debug('@@@@' + qe); // <-- Not being able to view this in setup>log>debug logs
        }
    }
}

Answer 1

Build your data structure in your controller class using a wrapper (AKA decorator) class such as this:

public class ArticleWrapper {
    public Article Art {get; set;}
    public FAQ__kav Faq {get; set;}
}

And then make your repeater loop round a list of the ArticelWrapper classes.

You can't use Visualforce repeaters in the same way you use for loops in apex - do the apex bit first, then use the repeater purely for generating the user interface.

Answer 2

I solved my problem using Visualforce Component. I am passing value from the page to this componet.

Here is my component:

<apex:component controller="PKB_DataForScraping_MobileController">
    <apex:attribute name="articleId" description="Article Id" type="Id" assignTo="{!artId}" required="true"/>
    {!Faq.Answer__c}
</apex:component>

I created controller for the component like Force Hero said:

public with sharing class PKB_DataForScraping_MobileController{ 
   public Id artId {
        get;
        set {
            artId = value;
        }   
   }

   public FAQ__kav getFaq() {
       try {
              faq = [select Answer__c, Links__c from FAQ__kav where PublishStatus = 'Online' and KnowledgeArticleId = :artId and IsVisibleInPkb = true];
       }
       catch (QueryException qe) {}
       return faq;
   }
} 

This is how I call this component from the page:

<c:PKB_SearchResultForScraping_Mobile articleid="{!a.Article_Id__c}" />      

This is equivalent of calling a method with parameters from Salesforce page.