NHibernate DateTimeOffsetType proxy source?

Question

I have an existing application using NHibernate to load some fairly complex objects from a database (SQL Server 2008 R2) that has been running for quite some time.

Today, I'm encountering the following error when trying to use JSON.Net to serialize my object:

Error getting value from 'DefaultValue' on 'NHibernate.Type.DateTimeOffsetType'.

None of the properties in my NHibernate mappings are using the DateTimeOffsetType, so I suspect that NHibernate is proxying my objects' properties to that somehow.

I have several Nullable DateTime values on my object, but nothing new to my current release.

Where should I be looking to figure out what properties NHibernate is trying use that type for?

What else might I be missing? The error comes when I attempt to serialize using this code:

 var converter = new IsoDateTimeConverter();
 x.Json = JsonConvert.SerializeObject(myObject, converter);

Again, that code has been in place for quite some time, it's just the problem that is new.

Answer 1

Not really the solution you will have been looking for perhaps, but a solution none the less - I encountered something similar. In my case I had forgotten to return my DTO from a web api call and the default json serialiser kicking in did this.

Now I map my data object over to a DTO object which has data contract attributes and I serialize that. Since my DTO is simple and doesn't get NHibernate Proxified this error no longer seems to occur.

Otherwise - I have done this for other Nullable Dates - where I want more control over the serialisation. Define a custom converter for it and do as you wish, but for this Nhibernate Type. I'd prefer not serialising (or trying to) those proxy types at all though.