How to serialize static or const member variables using JSON.NET?

Question

I haven't been able to find the answer to this anywhere, but when I try to serialize a struct or class with static or const member variables, they don't serialize by default. If I try to force serialization by setting MemberSerialization.OptIn, I get an error.

ex.

[JsonObject(MemberSerialization.OptIn)]
public class Test
{    
    [JsonProperty]
    public int x = 1;

    [JsonProperty]
    public static int y = 2;
}

If I try to serialize this class with:

Test t = new Test();
string s = JsonConvert.SerializeObject( t );

I get the error Error getting value from 'y' on 'Test'. The same happens if y is const.

My theory is that static and const values are stored somewhere special in memory, and for some reason the Json serializer dies trying to access them. That's entirely a hunch though, and I see nothing in the C# Reference for Static that's of any help. I'm relatively new to C# - and this is really a curiosity question more than anything at this point.

Answer 1

It could certainly serialize the static variable if it wanted to. Serialization is done by inspecting objects and types with the Reflection APIs, and those APIs allow you to do "anything" -- there is no technical reason these values cannot be serialized.

There is, however, a logical reason not to support this by default: it doesn't make much sense. You are serializing an instance, and static or const members are not logically part of an instance but of the class as a whole.

That said, you can still serialize static member if it's a property:

[JsonProperty]
public static int y { get; set; } // this will be serialized

And of course you can completely override the serializer's behavior by creating a custom JsonConverter.