public HttpResponseMessage Post(VariantModel variant) { HttpResponseMessage response; ModelsValidation validation = new ModelsValidation(); VariantData data = new VariantData(); if (ModelState.IsValid) { if (validation.DoesProductExist(variant.ProductId) == true) { data.SaveVariant(variant); response = Request.CreateResponse(HttpStatusCode.Created); } else { response = Request.CreateResponse(HttpStatusCode.NotFound, new { Message = "There is no product with given Id parameter." }); } } else { response = Request.CreateResponse(HttpStatusCode.NotFound, new { Message = "Model is invalid.", ModelValidation = "Product's id must be greater than 0. BasePrice, Tax and InStock must be a positive numbers." }); } return(response); }