Solr Issues Using Multilist Property on Search Result

Question

I have a multilist field on article items called Categories. In a module I am trying to filter based on one or more items in that multilist field. I can do this if I directly supply the name of the field in the index to use as follows:

var filterPredicate = PredicateBuilder.False<ArticleSearchResultItem>();

if (categories?.Any() == true)
{
   foreach (var category in categories)
   {
      filterPredicate = filterPredicate
         .Or(p => p["article_categories_sm"].Contains(category));
   }

   predicate = predicate.And(filterPredicate);
}

When I try to do this by adding article categories to my ArticleSearchResultItem it seems that the value the property gets is always null.

public class ArticleSearchResultItem : SearchResultItem
{
    [IndexField("publish_date")]
    public DateTime PublishDate { get; set; }

    [IndexField("article_categories")]
    public IEnumerable<ID> ArticleCategories { get; set; }
}

...

var categoryIds = categories?.Where(ShortID.IsShortID)
   .Select(cat => ShortID.Parse(cat).ToID());
if (categoryIds?.Any() == true)
{
   var filterPredicate = PredicateBuilder.False<ArticleSearchResultItem>();
   foreach (var category in categoryIds)
   {
      filterPredicate = filterPredicate
         .Or(p => p.ArticleCategories.Contains(category));
   }

   predicate = predicate.And(filterPredicate);
}

I tested having a suffix of _sm for the IndexField attribute above ArticleCategories and had the same results (all items were filtered when filtering by the same category that worked in the first block of code). Publish Date is also a custom field however that seems to be working fine (in queries shown by the search log it shows up as publish_date_tdt). When I look in the search logs it seems that using the property ArticleCategories causes the query to use article_categories_t which does not exist on my items. Could this be an issue with my schema or config? This instance is Sitecore.NET 8.2 (rev. 170614).

Answer 1

In case it works fine with p["article_categories_sm"].Contains(category) I suggest trying the following changes:

public class ArticleSearchResultItem : SearchResultItem
    {
        [IndexField("publish_date")]
        public DateTime PublishDate { get; set; }

        [IndexField("article_categories_sm")]
        [TypeConverter(typeof(Sitecore.ContentSearch.Converters.IndexFieldEnumerableConverter))]
        public virtual IEnumerable<ID> ArticleCategories { get; set; }
    }

I added the TypeConverter and made the field virtual.

If it doesn't work, trying without "_sm"

Answer 2

I would inspect the Search.log file to compare the queries that are actually sent to Solr for the working version and the non-working version, this approach has helped me many times in the past. You can also if need be paste the serialized query directly into the url of your solr instance:

https://localhost:8983/solr/#/core_name/query?q=SERIALIZED-QUERY

That way you can see what results get returned and tweak.

Answer 3

I uninstalled and reinstalled my solr instance and things started to work as expected using the code provided by @ArtsemPrashkovich's answer without the _sm suffix. I was running version 6.5 and switched it to be 5.1. According to the compatibility chart solr 6.5 was not supported by default for the version of Sitecore I was using: https://kb.sitecore.net/articles/227897.