Hello,

With DO 3.X PairTo was allowed on persistent interfaces, but it seems it's not possible anymore with DO4.

[HierarchyRoot]
  public class MyEntity : Entity, IHasItem
  {
    [Field, Key]
    public int Id { get; private set; }

    [Field]
    [Association(PairTo = "Owner")]
    public EntitySet<Item> Items { get; set; }
  }

  public interface IHasItem : IEntity
  {
    EntitySet<Item> Items { get; set; }
  }

  [HierarchyRoot]
  public class Item : Entity
  {
    [Field, Key]
    public int Id { get; private set; }

    [Field]
    public IHasItem Owner { get; set; }
  }

Xtensive.Storage.DomainBuilderException was unhandled
  Message=Paired field for field 'MyEntity.Items' should be assignable to type 'MyEntity'.
  Source=Xtensive.Storage
  StackTrace:
       at Xtensive.Storage.Building.Builders.AssociationBuilder.BuildPairedAssociation(AssociationInfo slave, String masterFieldName)
       at Xtensive.Storage.Building.Builders.ModelBuilder.BuildAssociations()
       at Xtensive.Storage.Building.Builders.ModelBuilder.BuildModel()
       at Xtensive.Storage.Building.Builders.ModelBuilder.Run()
       at Xtensive.Storage.Building.Builders.DomainBuilder.BuildModel()
       at Xtensive.Storage.Building.Builders.DomainBuilder.BuildDomain(DomainConfiguration configuration, DomainBuilderConfiguration builderConfiguration)
       at Xtensive.Storage.Upgrade.UpgradingDomainBuilder.BuildStageDomain(UpgradeStage stage)
       at Xtensive.Storage.Upgrade.UpgradingDomainBuilder.Build(DomainConfiguration configuration)
       at Xtensive.Storage.Domain.Build(DomainConfiguration configuration)

Am I missing something?

This is not an essential feature for us, but I thought I should give you the information.

This thread was imported from our support forum. The original discussion may contain more detailed answer.