NHibernate setting access="field.camelcase-underscore" fails in version 3

Question

I have a solution that was created with NHib 1.2 which we're upgrading to NHib 3.0.

Our hbm file has the following property:

<property name="ContentId" column="ContentId" access="field.camelcase-underscore" />

The class doesn't have a ContentId property. This was working fine in NHib 1.2 but now we're getting getting the following exception:

Could not compile the mapping document: XXXX.Core.Domain.Video.hbm.xml ---> NHibernate.MappingException: Problem trying to set property type by reflection ---> NHibernate.MappingException: class Core.Domain.Video, Core, Version=1.0.0.29283, Culture=neutral, PublicKeyToken=null not found while looking for property: ContentId ---> NHibernate.PropertyNotFoundException: Could not find the property 'ContentId', associated to the field '_contentId', in class 'Core.Domain.Video'.

Why would this stop working? Is it still supported in NHib 3?

We have many many properties like this that we might need to add.

Answer 1

NHibernate greatly improved its error messaging and diagnostics in NH2.X and again in NH3.X. You are telling NHibernate that you have a property and you want to map it via field access to a field named by _camelCase convention. You don't have a property named ContentId and NHibernate is letting you know that you lied to it. :)

Try updating your mapping to:

<property name="_contentId" column="ContentId" access="field" />

You will need to update any HQL or Criteria queries to use _contentId rather than ContentId. Another option would be to add a private ContentId property.

Answer 2

I'd like to provide information which helped me answer this question:

http://groups.google.com/group/nhusers/browse_thread/thread/e078734a221c3c0c/ec8b873b385d4426?lnk=gst&q=field+camelcase+underscore#ec8b873b385d4426

In this link Fabio explains the same problem you are having like this:

This mapping

<property name="PositiveValue" access="field.camelcase-underscore" />

mean: For my property named "PositiveValue" you (NH) have to access to the field; to discover which is the associated field you (NH) have to use the strategy "camelcase-underscore".

If there is no property you can't use the accessor with a specific strategy.

Which struck me as a little odd because it meant adding dummy, unused properties, just to make the nhibernate3 compiler happy. The underlying functionality is the same.