Description

Automatic type conversion might not work for the IEnumerable<T> type when mapping index document fields to properties. An example of the affected properties looks like this:

public class MySearchItem
{
    [IndexField("treelist")]
    public IEnumerable<Guid> TreeList { get; set; }
    [IndexField("multilist")]
    public IEnumerable<ID> MultiList{ get; set; }
}

In this case, the TreeList and MultiList properties remain unassigned (null) even if the search result includes a valid value in the "treelist_sm" and "multilist_sm" field.

Solution

To resolve the issue, consider one of the following options:

• Upgrade a Sitecore XP instance to Sitecore XP 10.3.0.
• Add a typeMatch for the IEnumerable<Guid> and IEnumerable<ID> type by creating a configuration patch file in the \App_Config\Include\zzz folder:

  <?xml version="1.0" encoding="utf-8" ?>
  <configuration xmlns:patch="http://www.sitecore.net/xmlconfig/" xmlns:set="http://www.sitecore.net/xmlconfig/set/" xmlns:role="http://www.sitecore.net/xmlconfig/role/" xmlns:search="http://www.sitecore.net/xmlconfig/search/">
    <sitecore role:require="Standalone or ContentManagement or ContentDelivery" search:require="solr">
      <contentSearch>
        <indexConfigurations>
          <defaultSolrIndexConfiguration>
            <fieldMap>
              <typeMatches hint="raw:AddTypeMatch">
                <typeMatch typeName="guidEnumerable" type="System.Collections.Generic.IEnumerable`1[System.Guid]"                         fieldNameFormat="{0}_sm" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" /> 
                <typeMatch typeName="idEnumerable"   type="System.Collections.Generic.IEnumerable`1[[Sitecore.Data.ID, Sitecore.Kernel]]" fieldNameFormat="{0}_sm" multiValued="true" settingType="Sitecore.ContentSearch.SolrProvider.SolrSearchFieldConfiguration, Sitecore.ContentSearch.SolrProvider" />
              </typeMatches>
            </fieldMap>
          </defaultSolrIndexConfiguration>
        </indexConfigurations>
      </contentSearch>
    </sitecore>
  </configuration>

• Change the return type of the properties from IEnumerable<Guid> and IEnumerable<ID> to List<Guid>:

  public class MySearchItem
  {
      [IndexField("treelist")]
      public List<Guid> TreeList { get; set; }
      [IndexField("multilist")]
      public List<Guid> MultiList{ get; set; }
  }