AngularJS和WebApi POST在ApiController中变为null

Question

  

这是WebApi控制器...在本代码中我得到一个null（产品）意味着当我发布数据时我得到产品为空。

// POST: api/Products
        [ResponseType(typeof(Product))]
        public IHttpActionResult PostProduct(Product product)
        {
            Product p = new Product();
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            p.ProductName = product.ProductName;
            p.ProductDes = product.ProductDes;
            p.AddCatagoryId = product.tblcatagory.Id; 
            p.AddSubCatagoryId = product.tblsubcatagory.Id; 
            p.Date = DateTime.Now.Date;
            p.Inches = product.Inches;
            p.ProductQty = product.ProductQty;
            p.ProductRate = product.ProductRate;
            db.products.Add(p);
            db.SaveChanges();

            return CreatedAtRoute("DefaultApi", new { id = product.Id }, product);
        }

  

Angular Js Code ....我在（alert（））中得到了正确的Pro值，但是当它转到这个POST：api / Products链接比我面对空值...你可以看到上面的代码。

$scope.submitProForm = function (isValid, Pro) {
        if (isValid) {
            alert(Pro.tblcatagory.Id);   //here i get a corect value after load application
            alert(Pro.ProductName);      //here i get a corect value after load application
            //cfpLoadingBar.start();
            $http.post('/api/Products', Pro).then(function (response) {
                //cfpLoadingBar.complete();
                GetAllPro();
                Notification.success('Data Added Successfully!');
            },
                function () {
                    Notification.error('Something Went Wrong!');
                })
        }

    }