【XAF问题】多个属性验证RuleUniqueValue

[RuleCombinationOfPropertiesIsUnique("SampleRule", DefaultContexts.Save, "Description, Id")]
public class SampleClass : BaseObject {
    private int id;
    private string description;

    public SampleClass(Session session) : base(session) { }

    public int Id {
        get { return id; }
        set { SetPropertyValue("Id", ref id, value); }
    }
    public string Description {
        get { return description; }
        set { SetPropertyValue("Description", ref description, value); }
    }
}