public DiseasesType(IDiseaseRepository diseaseRepository) { Field(x => x.Id, type: typeof(IdGraphType)).Description("Disease Id"); Field(x => x.Description).Description("Description of a disease"); Field(x => x.DiseaseName).Description("Name of the Disease"); FieldAsync <ListGraphType <PersonalDiseasesType>, IReadOnlyCollection <PersonalDisease> >( "personsWithDisease", "returns list of persons with this disease", resolve: context => { return(diseaseRepository.GetPersonsByDiseaseId(context.Source.Id)); }); }