How Do I display an aggregateResult list in a visualforce pageBlockTable?

Question

I have a class that is correctly pulling an AggregateResult in from a child object on a custom object. I'd like to use an pex:pageBlockTable to display the aggregateResults but when trying to setup the header I get an error.

This works per system debug checks:

    public List<AggregateResult> getAggregateList(){
            Parent_Custom_object__c TheCS = (Parent_Custom_object__c)sc.getRecord();
            List<AggregateResult> AggResults = new List <AggregateResult>();

         AggregateResult[] aggQuery = [select
     zone__c zone,
      SUM(Added_Value__c)TotalAddedValue,
      SUM(delivered_units__c)TotalDelivered
      from Custom_Child_object__c 
      where Parent_of_Custom_Child_object__c =:TheCS.id
      GROUP BY zone__c    
             ]; 

     if(aggQuery!=null){
         for(AggregateResult QAR:aggQuery)
      {
        AggResults.add(QAR); 
    }

Visualforce page:

<apex:pageBlock title="AggregateList">   

     <apex:pageBlockTable value="{!AggregateList}" var="d" id="Zone" title="Aggregate"> 
     <apex:column value="{!d.Zone}" headervalue="Zone" ></apex:column>
 </apex:pageBlockTable> 

Error: Error: Invalid field Zone for SObject AggregateResult

Answer 1

You can only use the dot-notation for "concrete" fields (fields that can be verified through metadata). For example, {!Account.Name} is valid, because the system can verify that Account.Name is a real field. However, AggregateResult is a dynamic object. As such, you need to use the "dynamic" syntax:

<apex:column value="{!d['Zone']}" headerValue="Zone" />

The [field] notation allows you to use a string variable to dynamically access a field that may or may not exist on an sObject or AggregateResult variable.