[SalesForce] Reference inner class in Visualforce component

I'm trying to build a VF component that references an attribute that is an instance of an inner class. I followed the suggestion here on the Apex boards but it does not compile for me using V28.0. (Note the boards post was about lists of inner class objects – I only need a single instance)

Interface, Apex class, VF component follow:

public interface VFComponentAttributable {
// To make inner classes available as VF component attributes
// http://boards.developerforce.com/t5/Visualforce-Development/Error-using-inner-class-in-component-attribute/td-p/147856
}

public with sharing class Foo {
   public class InnerBar implements VFComponentAttributable{
      public String  myVbl {get; set;}
  }
}    


<apex:component >
<!-- Generates compiler error 'Unknown property VFComponentAttributable.myVbl' -->
<apex:attribute name="bar"                      description="instance of inner class"
                type="VFComponentAttributable"          required="true"/>

<apex:outputText value="{!bar.myVbl}"/>  


<!-- This doesnt work either, generates compiler error  'Apex class InnerBar does not exist
<apex:attribute name="bar"                      description="instance of inner class"
                type="Foo.InnerBar" required="true"/>
<apex:outputText value="{!bar.myVbl}"/>             -->

I know I can refactor and make the inner class an outer class and it will work but I'd rather not if I can avoid it.

Best Answer

I've run across this as well and also resorted to refactoring my inner-class to the top level. The documentation isn't clear on this, but considering that the type attribute is considered limited, I think it's fair to assume that only top-level classes are supported. From the Visualforce Developer's Guide (pg. 285):

Only the following data types are allowed as values for the type attribute:

Primitives, such as String, Integer, or Boolean.
sObjects, such as Account, My_Custom_Object__c, or the generic sObject type.
One-dimensional lists, specified using array-notation, such as String[], or Contact[].
Maps, specified using type="map". You don't need to specify the map's specific data type.
Custom Apex types (classes).

Related Solutions

[SalesForce] Error Attempt to de-reference a null object in component class

You have a lot of problems in your code, but to answer the first question: you never initialized aData, so it is null.

// init the controller and display some sample data when the page loads
  public AccountSearchController() {
    aData = new CLSearchDataClass(); // Initialize here
    soql = 'select Id, name, Industry, Zip_Postal_Code__c, Owner.id, parent.name, parent.id, Country_Code__c from account where name != null';  
    runQuery();
  }

Secondly, you're "lazy-loading" way too much. Only use the technique if you don't know if you need the data (it appears you always do, so you may as well initialize everything in the constructor).

This line here will always execute:

  if(isSelected = true){

Using a single equals sign is an assignment, which results in isSelected always being set to true, and the branch is always executed (because the return value is true). Use == instead.

For some minor optimizations:

    if(accounts.size() > 0){
        for (Account acc : accounts)
        {
            if(acc.Id != null){
            options.add(new SelectOption(acc.Id, acc.Name));
            }
        }
    }

It's legal to iterate over an empty list, and checking for empty beforehand just wastes CPU time and makes code more verbose. Also, since acc is coming from a query, Id will never be null.

    for (Account acc : accounts) {
        options.add(new SelectOption(acc.Id, acc.Name));
    }

public PageReference runSearchA() {
    ...
    return null;
}

If you're never going to redirect, just use void. Returning a PageReference suggests that you could redirect, which is misleading. Doubly so if someone is using the Summary view of your class.

Reference a VisualForce component attribute to use in itself

You can't reference a component's attributes that way in Visualforce. You can only reference public Apex variables and methods, and Visualforce variables (e.g. from apex:pageBlockTable or apex:variable). As an aside, you only use ! at the beginning of a merge field, and you don't use .get on a Map, but just the ordinary map[key] notation. {wrappers[test.title]} would have been the appropriate way to reference the value, if it were allowed.

Best Answer

Related Solutions

[SalesForce] Error Attempt to de-reference a null object in component class

Reference a VisualForce component attribute to use in itself

Related Topic