routes.MapHttpRoute(
                name:"DinnerApplicationApi",
                routeTemplate: "api/dinner/{dinnerId}/{controller}"
                );

[ModelValidationFilter]
        public HttpResponseMessage Post([FromBody]ApplicationApiModel application, int dinnerId)
        {
            //this will work when invoked from route /dinner/dinnerId/application and without ModelValidationFilter
            application.dinnerId = dinnerId;
            if (123456 == application.dinnerId)
            return new HttpResponseMessage(HttpStatusCode.OK);
            else
            {
                return new HttpResponseMessage(HttpStatusCode.BadRequest);
            }
        }

public class ApplicationApiModel
    {
        [Required]
        public int DinnerId { get; set; }
        [Required]
        public AttendeeApiModel Attendee { get; set; }
        public string Message { get; set; }
        public string Password { get; set; }

    }