Umbraco - Using Examine to search Umbraco.Tags

I have a umbraco doctype with a field that is of type Umbraco.Tags.

Using examine to search the field like this:

var searchEngine = ExamineManager.Instance.SearchProviderCollection["ExternalSearcher"];
            var searchCriteria = searchEngine.CreateSearchCriteria(BooleanOperation.Or);

            var query = searchCriteria.Field("title", searchTerm)
            .Or().Field("topicTags", searchTerm).Compile();
var results = searchEngine.Search(query);

I know for a fact that the value is inside topicTags, but it result is 0...

Any ideas?

Update: It turns out the reason why no results are found is because the Umbraco.Tags datatype stores data like this: tag1,tag2,tag3 with no spaces, so tag1 is not in the index, I would have to search for "tag1,tag2,tag3" to get a hit.

Looks like I might have to high-jack the Examine index event and change the way the data is indexed.

These is a built in umbraco data type, surely there is a way to search it.

Yes your right, the reason why I was getting 0 was the tags are stored like this:

tag1,tag2,tag3. 

With no spaces.

So tag1,tag2,tag3 would result in a hit, but tag1 wouldn't.

The solution was to hook in to the umbraco publish event and change the way that field is indexed. Solution:

 public class ExamineEvents : ApplicationStartupHandler
{
public ExamineEvents()
{
    ExamineManager.Instance.IndexProviderCollection["ExternalIndexer"].GatheringNodeData +=
        ExamineEvents_GatheringNodeData;
}


private void ExamineEvents_GatheringNodeData(object sender, IndexingNodeDataEventArgs e)
{
                if (e.IndexType != IndexTypes.Content) return;

    // Node picker values are stored as csv which will not be indexed properly 
    // We need to write the values back into the index without commas so they are indexed correctly
    var fields = e.Fields;
    var searchableFields = new Dictionary<string, string>();
    foreach (var field in fields)
    {
        switch (field.Key)
        {
            case "topicTags":

                var searchableFieldKey = "topicTagsIndexed";
                var searchableFieldValue = field.Value.Replace(',', ' ');
                if (!string.IsNullOrEmpty(searchableFieldValue))
                {
                    searchableFields.Add(searchableFieldKey, searchableFieldValue);
                }
                break;
        }
    }

    foreach (var fld in searchableFields)
    {
        e.Fields.Add(fld.Key, fld.Value);
    }
}

Then when you create your search query you search in the field topicTagsIndexed

SearchCriteria.Field("pagetitle", searchTerm).Or().Field("topicTagsIndexed", searchTerm).Compile();

Hope this helps someone else.