Web API Error: The 'ObjectContent`1' type failed to serialize the response body for content type

Question

I am getting this error when attempting to use a Web API controller.

Web API Error: The \'ObjectContent`1\' type failed to serialize the response body

Answer 1

If you don't need the lazy-loaded navigation properties provided by the proxy class (System.Data.Entity.DynamicProxies.Student_4C97D068E1A...), you can disable their generation by setting:

unitOfWork.Configuration.ProxyCreationEnabled = false;

What to do if you need the proxy class is another question.

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Follow these links for a good overview of lazy loading and proxies:

• Loading Related Entities
• Working with Proxies
• Should I enable or disable dynamic proxies

I usually disable lazy loading and proxies by default, and enable one or both in specific code blocks that need them.