Web API Getting Http 500 error - asp.net-mvc-4

Question

Here is my MVC Controller and everything is fine:
private UnitOfWork UOW;
public InventoryController()
{
UOW = new UnitOfWork();
}
// GET: /Inventory/
public ActionResult Index()
{
var products = UOW.ProductRepository.GetAll().ToList();
return View(products);
}
Same method call in API Controller gives me an Http 500 Error:
private UnitOfWork _unitOfWork;
public TestController()
{
_unitOfWork = new UnitOfWork();
}
public IEnumerable<Product> Get()
{
var products = _unitOfWork.ProductRepository.GetAll().ToList();
return products;
}
Debugging shows that indeed there is data being returned in both controllers' UOW calls. I then added a customer configuration in Global:
public static void CustomizeConfig(HttpConfiguration config)
{
config.Formatters.Remove(config.Formatters.XmlFormatter);
var json = config.Formatters.JsonFormatter;
json.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
}
I am still receiving an Http 500 in API Controller ONLY and at a loss as to why. Any ideas?
UPDATE:
It appears using lazy loading caused the problem. When I set the associated properties to NON-VIRTUAL the Test API provided the necessary JSON string. However, whereas before I had the Vendor class included, I only have VendorId. I really wanted to included the associated classes. Any ideas? I know there are alot of smart people out there. Anyone?

Answer 1

Problem Solved:
The issue was not Lazy Loading after all. The issue was that while I correctly had an association of Vendor in product, I also had a collection of products in Vendor, presumably causing something circular:
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public int VendorId { get; set; }
public virtual Vendor Vendor { get; set; }
}
public class Vendor
{
public int Id { get; set; }
//public Vendor()
//{
// Products = new List<Product>();
//}
public string CompanyName { get; set; }
// public ICollection<Product> Products { get; set; }
}
Omitting the collection in Vendors and reinstating the virtual in Products did the trick.
"vendor": {
"id": 4,
"companyName": "Vendor 3"
},
"id": 1,
"name": "Product 1",
"vendorId": 4
},
{
"vendor": {
"id": 2,
"companyName": "Vendor 4"
},
"id": 2,
"name": "Product 2",
"vendorId": 2
},
{
"vendor": {
"id": 3,
"companyName": "Vendor 2"
},
"id": 3,
"name": "Product 3",
"vendorId": 3
},
{
"vendor": {
"id": 1,
"companyName": "Vendor 1"
},
"id": 4,
"name": "Product 4",
"vendorId": 1
}]