Could not resolve property

Gradiation · **Joined:** Fri Apr 27, 2007 11:50 am **Posts:** 23

Hi Guys,

I've hit across a problem and keep getting the error

Code:

could not resolve property: User.Email of: Core.Domain.NewsletterSubscription

Whilst i know this usualy revolves around an incorrect mapping, the weird thing is a different query that queries agains "User.Id" works.

The code for the 2 functions are:

Code:

        public NewsletterSubscription GetByEmail(string email)
        {
            ICriteria criteria = NHibernateSession.CreateCriteria(typeof(NewsletterSubscription));
            criteria.Add(Expression.Eq("User.Email", email));
            return criteria.UniqueResult<NewsletterSubscription>();
        }

        public NewsletterSubscription GetByUser(User user)
        {
            ICriteria criteria = NHibernateSession.CreateCriteria(typeof(NewsletterSubscription));
            criteria.Add(Expression.Eq("User.Id", user.Id));
            return criteria.UniqueResult<NewsletterSubscription>();
        }

With the mapping file for the NewsletterSubscription class being:

Code:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="Core.Domain.NewsletterSubscription, Core" table="`NewsletterSubscription`" lazy="false">

    <id name="Id" column="`NewsletterSubscriptionId`" unsaved-value="00000000-0000-0000-0000-000000000000">
      <generator class="guid" />
    </id>
     
    <property name="Email" access="nosetter.camelcase-underscore" />
   <property name="IsVerified" />
   <property name="IsActive" />
    <property name="CreatedDate" />
   <property name="ModifiedDate" />
   
   <many-to-one name="User" class="Core.Domain.User, Core" column="`UserId`" not-null="false" />

  </class>
</hibernate-mapping>

Anybody got any ideas why one would work, but the other throws the said error?

wolli · **Posted:** Wed Sep 03, 2008 3:08 am

Probably the "Id" property is handled differently. Without creating the association criteria (CreateCriteria, CreateAlias) User.Id will internally be translated to column "userid" from table NewsletterSubscription.
When you use User.Email you definitely need the join because that information is only available on table User.

Gradiation · **Joined:** Fri Apr 27, 2007 11:50 am **Posts:** 23

Hey wolli,

Thanks for the pointers.

Just one other question. The NewsletterSubscription entity has a property "Email" of it's own, which it's getter is:

Code:

get { return (User != null)? User.Email : _email; }

Should this work within the context of the NHibernate query? or will it just check against the field in the database?

Many thanks

Matt

wolli · **Posted:** Wed Sep 03, 2008 4:33 am

You can only use "mapped" properties/fields in a query/criteria. In your case you have to use:

Code:

criteria.CreateCriteria("User", "u")
       .Add(Expression.Eq("u.Email", email));

Gradiation · **Joined:** Fri Apr 27, 2007 11:50 am **Posts:** 23

Hey wolli,

Thanks for your help, i've ended up with the following as i need to check both fields:

Code:

ICriteria criteria = NHibernateSession.CreateCriteria(typeof(NewsletterSubscription));
            criteria.CreateAlias("User", "u", JoinType.LeftOuterJoin);
            criteria.Add(
                Expression.Or(
                    Expression.Eq("Email", email),
                    Expression.Eq("u.Email", email)
                )
            );
            return criteria.UniqueResult<NewsletterSubscription>();

Many thanks