Getting "unable to cast PersistentGenericSet to ISet" error

Question

I get this error:

Unable to cast object of type 'NHibernate.Collection.Generic.PersistentGenericSet1[IocWinFormTestEntities.People]' to type 'System.Collections.Generic.ISet1[IocWinFormTestEntities.People]'.

The entity:

public class Event 
{
    public Event()
    {
        this.People = new HashSet<People>();
    }
    public virtual Guid Id { get; private set; }

    public virtual ISet<People> People { get; set; }
}

Map override class:

public class EventMapOverride : IAutoMappingOverride<Event>
{
    public void Override(AutoMapping<Event> mapping)
    {
        mapping.HasMany(c => c.People)
            .AsSet()
            .Cascade.AllDeleteOrphan();
    }
}

Generated hbm from fluent automapper:

<set cascade="all-delete-orphan" name="People">
    <key>
        <column name="Event_id" />
    </key>
    <one-to-many class="IocWinFormTestEntities.People, IocWinFormTestEntities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
</set>

What's wrong?

score 32 · Accepted Answer · edited May 12 '17 at 06:56

32

Your problem is you are using ISet in System.Collections.Generic namespace but nHibernate expects ISet to be Iesi.Collections.Generic.ISet<>. So change your property definition to

public virtual Iesi.Collections.Generic.ISet<People> People { get; set; }

If you want to use .net 4 ISet<> interface, go through this article

edited May 12 '17 at 06:56

tinonetic

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answered Jun 07 '11 at 23:40

Eranga

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Link redirects to home, seems to be dead. – Platinum Azure Jun 06 '16 at 21:32

score 14 · Answer 2 · answered Jun 07 '11 at 23:45

14

The latest NHibernate uses Iesi.Collections.ISet, not System.Collections.Generic.ISet. You can either reference the Iesi assembly or use System.Collections.Generic.ICollection:

public virtual ICollection<People> People { get; set; }

The ISet interface inherits from ICollection.

answered Jun 07 '11 at 23:45

eulerfx

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But last time I tried ICollection for , NHib was always rewriting it with a plain Array instead of my original HashSet... – JustAMartin Feb 22 '13 at 09:32

score 4 · Answer 3 · edited Jan 18 '17 at 01:08

4

With Nhibernate 4, using System.Collections.Generic.ISet<> is now the way to go.

The error showcased in this question should no longer occur.

edited Jan 18 '17 at 01:08

Ted

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answered Mar 24 '16 at 10:47

Frédéric

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Getting "unable to cast PersistentGenericSet to ISet" error

3 Answers3

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