BoolQuery.cs

.Query(q =>
                   q.ConstantScore(cs =>
                       cs.Filter(f =>
                           f.Bool(bq =>
                               bq.Should(
                                   bs => bs.Term(p => p.Names.First().Firstname, form.Query),
                                   bs => bs.Term(p => p.Names.First().Lastname, form.Query),
                                   bs => bs.Term(p => p.Names.First().Companyname, form.Query)
                                   )
                                 )
                   )
)