DataMember.Name ignored by WCF JSON serialization?

Question

I have a WCF service to which I am adding new endpoints that use idiomatic HTTP+JSON. I bumped into the DateTime formatting issue, and tried to fix it like this:

[DataContract]
public class PingResponse
{
    [IgnoreDataMember] public DateTime SystemDateTimeLocal;
    [IgnoreDataMember] public DateTime SystemDateTimeUTC;
    [DataMember] public string Version;

    [DataMember(EmitDefaultValue = false, Name = nameof(SystemDateTimeLocal)), EditorBrowsable(EditorBrowsableState.Never)]
    public string SystemDateTimeLocalFormatted
    {
        get => SystemDateTimeLocal.ToString(Constants.DateTimeFormat);
        set => SystemDateTimeLocal = DateTime.ParseExact(value, Constants.DateTimeFormat, CultureInfo.InvariantCulture);
    }

    [DataMember(EmitDefaultValue = false, Name = nameof(SystemDateTimeUTC)), EditorBrowsable(EditorBrowsableState.Never)]
    public string SystemDateTimeUTCFormatted
    {
        get => SystemDateTimeUTC.ToString(Constants.DateTimeFormat);
        set => SystemDateTimeUTC = DateTime.ParseExact(value, Constants.DateTimeFormat, CultureInfo.InvariantCulture);
    }
}

But, the resulting object is serialized with SystemDateTimeLocalFormatted and SystemDateTimeUTCFormatted properties, ignoring the Name on the DataMember attributes. Is there a way to achieve what I want that doesn't involve swapping out the serialization stack? :-P

---

Update: I just copied this type into a test app and explicitly used DataContractJsonSerializer and it did not ignore the Name field -- so I am forced to conclude that the original project is archieving its JSON serialization with a different serializer. I haven't yet looked into identifying which one.

Answer 1

I have found the cause. It's a weird one. I found a dummy DataContractAttribute.cs in our project. This was silently taking the place of the real DataContractAttribute , so that DataContractJsonSerializer didn't detect the type having a data contract. Removing the DataContractAttribute.cs from the project so that the source code instead uses the real System.Runtime.Serialization.DataContractAttribute has resolved the problem.