I'm using Umbraco 7 to index a multi node picker so I can replace the coma separation with spaces.

This is the code I am using but all the default index return null.

using System;
using System.Text;
using System.Xml.Linq;
using Examine;
using umbraco.BusinessLogic;
using UmbracoExamine;

namespace Site.App_Code
{
    public class ExamineEvents : ApplicationBase
    {

        public ExamineEvents()
        {
            var y = ExamineManager.Instance;
            var x = ExamineManager.Instance.IndexProviderCollection["UmbracoExamine.UmbracoContentIndexer"];
            var b = ExamineManager.Instance.IndexProviderCollection["ExamineLuceneIndexSets"];
            var c = ExamineManager.Instance.IndexProviderCollection["InternalIndexSet"];

            ExamineManager.Instance.IndexProviderCollection["ExternalIndexSet"].GatheringNodeData += ExamineEvents_GatheringNodeData;

        }


        void ExamineEvents_GatheringNodeData(object sender, IndexingNodeDataEventArgs e)
        {
            GatheringNodeDataHandler(e);
        }

        private void GatheringNodeDataHandler(IndexingNodeDataEventArgs e)
        {
            //grab the current data from the Fields collection
            var mntp = e.Fields["sector"];
            //let's get rid of those commas!
            mntp = mntp.Replace(",", " ");
            //now put it back into the Fields so we can pretend nothing happened!
            e.Fields["sector"] = mntp;
        }
    }
}