[SalesForce] Retrieve data from custom object on Visualforce page

I have created a custom object which contains multiple fields that I want to be able to show on a Visualforce page. From the discussion I've had with another developer it was recommended that I use a utility class and just reference that from the standard class. Here's what I've got.

Utility class

public without sharing class pkb_content_Utility {
  public PKB_Content__c pos{get;set;}
  public pkb_Controller() {
    pos = [SELECT Home_Forum__c FROM PKB_Content__c];
  }
}

While I only reference Home_Forum__c, there are multiple other fields I need to reference as well but I am unsure of the best way to do this.

Main controller class

pos = pkb_content_Utility.pkb_Controller();

Visualforce code

<apex:page showHeader="false" standardController="KnowledgeArticle" extensions="pkb_Controller">
  <apex:outputText value="{!pos.Home_Forum__c}"/>
</apex:page>

Best Answer

Adding ApexPages.StandardController sc as a constructor argument (that can be used to get a reference the KnowledgeArticle if that is needed) makes the class fit the controller extension pattern that it looks like you are aiming for based on your page:

public without sharing class PkbContentController {
      public PKB_Content__c pos {get;set;}
      public PkbContentController(ApexPages.StandardController sc) {
          // Add all the other fields you need here instead of ...
          pos = [SELECT Home_Forum__c, ... FROM PKB_Content__c limit 1];
      }
}

This pattern "mixes in" the controller extension with the standard controller so your page can reference both; in your example you are only referencing the controller extension field:

<apex:page showHeader="false"
        standardController="KnowledgeArticle"
        extensions="PkbContentController">
    <apex:outputText value="{!pos.Home_Forum__c}"/>
    <!-- Output more fields here -->
</apex:page>

See e.g. the Building a Controller Extension documentation for more information.

Related Solutions

[SalesForce] Updating fields from multiple objects on a single visualforce page

Ed - Two excellent doc references for you to learn from --

1) http://www.developerforce.com/guides/Visualforce_in_Practice.pdf and

2) https://www.packtpub.com/application-development/visualforce-development-cookbook

both are superb.

You have a conceptual issue in your example in that a VF page is associated with a controller (standard, standard w/ extensions, or custom) and the merge field references have to be to objects known to that controller. So, if you literally want to refer to {!ObjectA.xxx} and {!ObjectB.xxx} then the page's controller has to have either public getMethods or public getters for these specific objects. A page with standardController="ObjectA" has implicit reference to ObjectA's fields and these can be updated. But if you don't have an extension class or go the full custom controller route, ObjectB is unknown

[SalesForce] How do i map key value pairs to custom objects in a list

You will need to create a wrapper class and use that as your collection type. Something like:

public List<EventLocationWrapper> locations { get; private set; }

public class EventLocationWrapper
{
    public Event_Location__c record { get; private set; }
    public Object otherProperty { get; private set; }

    public EventLocationWrapper(Event_Location__c record)
    {
        this.record = record;
        this.otherProperty = 'Some value';
    }
}

Example

After you have a wrapper class, your controller might be written like this:

public with sharing class EventDataExt {

    private final Event__c e;

    public EventDataExt(ApexPages.StandardController stdController) {
        this.e = (Event__c)stdController.getRecord();
    }

    public List<EventLocationWrapper> getelWrappers () {

        // query for the events - this list never be null, but may be empty
        List <Event_Location__c> els = [select Name, City__c from Event_Location__c where Event__c=:e.Id];

        // create the list of EventLocationWrapper to be returned
        List<EventLocationWrapper> eventLocationWrappers = new List<EventLocationWrapper>();

        // for each item in the query list add it to the wrapper and augment with additional values
        for (Event_Location__c el : els) {

            // use the constructor to place this event inside the wrapper
            EventLocationWrapper wrapper = new EventLocationWrapper(el);

            // add some additional stuff
            wrapper.otherProperty = "Something Else";

            // add the wrapper to the list to be returned
            eventLocationWrappers.add(wrapper);
        }

        return eventLocationWrappers;       
    }

    public class EventLocationWrapper
    {
        public Event_Location__c record { get; set; }
        public String otherProperty { get; set; }

        public EventLocationWrapper(Event_Location__c record)
        {
            this.record = record;
            this.otherProperty = 'Some value';
        }
    }
}

The VF markup to reference a wrapper like this might look similar to this pseudocode:

<apex:dataTable value="{!elWrappers}" var="wrapper">

    <!-- value from the wrapper itself -->
    <apex:outputText value="{!wrapper.otherProperty}" />

    <!-- value from the sObject within the wrapper -->
    <apex:outputField value="{!wrapper.record.City__c}" />
</apex:dataTable>

Best Answer

Related Solutions

[SalesForce] Updating fields from multiple objects on a single visualforce page

[SalesForce] How do i map key value pairs to custom objects in a list

Example

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