Web API converted to Azure Mobile Service not serializing all properties

Question

I have a working Web API that i am converting to a .Net Azure Mobile Service. The API returns a complex model - objects with properties - some of which are collections of other objects. This works as expected with plain Web API but with Azure Mobile Services I have an issue where one of my models does not have all it's properties serialized.

When i set a break point on the return statement in the controller, I see that all the properties and their values are present. This leads me to believe that the issue is with serialization (JSON).

return Request.CreateResponse(HttpStatusCode.OK, myModel);

Examples of properties that are being serialized:

public Guid Id { get; set; }
public IEntityDto ModelDto { get; set; } //this is an object with many properties all of which serialize

Examples of properties that are NOT being serialized:

public ItemStatus Status { get; set; }  //this is an enum
public string Message { get; set; }
public string TestProp { get; set; } //this is a simple string property I added to help debug

How can I go about further debugging this so that i can see why these properties are being excluded?

Note: At the moment I am still running this locally not off Azure. This is with Visual Studio 2013 Update 2 RTM.

UPDATE: Upon closer inspection it appears that the properties not being serialized are properties that are either enums or have a value of null.

Don't you think to post which properties are serialized and which are not. Or do you expect us to make guesses blindly. — L.B, Jun 18 '14 at 21:26
I've updated the question to include example properties. I was actually just looking for guidance on how to debug the serializer but your nudge for more info made me notice that the properties in question are either enums or have a value of null. — user1843640, Jun 18 '14 at 21:52
Does the value of the enum property have the default value for the enum? By default the JSON serializer will not serialize those fields with default values (which is the case for `null` in object types). — carlosfigueira, Jun 19 '14 at 01:27
@carlosfigueira That was it! For anyone reading, this behavior can be changed by setting: `HttpConfiguration.Formatters.JsonFormatter.SerializerSettings.DefaultValueHandling` — user1843640, Jun 19 '14 at 02:43
Can you post your comment as an answer (and accept it) so that other people can learn from what you did? Thanks! — carlosfigueira, Jun 19 '14 at 20:01

score 5 · Accepted Answer · edited Oct 01 '16 at 16:34

As @carlosfigueira mentioned in a comment to the original question, the default behavior of the JSON serializer is to exclude properties with null and default values. To address this I changed the following settings:

  httpConfig.Formatters.JsonFormatter.SerializerSettings.DefaultValueHandling = Newtonsoft.Json.DefaultValueHandling.Include;
  httpConfig.Formatters.JsonFormatter.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Include;

...where httpConfig is of type HttpConfiguration. You can make these changes on app start - in a config file like WebApiConfig.cs or directly in Global.asax.cs.

Web API converted to Azure Mobile Service not serializing all properties

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