service.cs

var response = _client.Search<ElasticFileInfo>(s => s
                .Index(_indexName)
                .From(0)
                .Size(10000)
                .Query(qry => qry.QueryString(q => q.Query(queryString)))
                .StoredFields(f => f.Fields(p => p.CreatedBy))
                .Aggregations(a => a
                    .Terms("types", st => st
                        .Field(f => f.Type))
                    .Terms("addedby", st => st
                        .Field(f => f.CreatedBy.Suffix("keyword")))
                )
            );