private void AddNotificationQueries(NotificationFacade notificationFacade) { Field <ListGraphType <NotificationType> >( "allNotifications", resolve: context => notificationFacade.GetAll() ); Field <NotificationType>("notification", arguments: new QueryArguments(new QueryArgument <IntGraphType> { Name = "id" }), resolve: context => { var id = context.GetArgument <int?>("id"); return(id != null ? (notificationFacade.GetById((int)id)) : null); } ); Field <ListGraphType <NotificationType> >("notificationsByGroupId", arguments: new QueryArguments(new QueryArgument <NonNullGraphType <IntGraphType> > { Name = "groupId" }), resolve: context => { var groupId = context.GetArgument <int>("groupId"); return(notificationFacade.GetByGroupId(groupId)); } ); }