Question

I have a problem here and no have ideia to solution this.

I have 2 classes:

public class Previa
    {
        public virtual int Id { get; set; }
        public virtual DateTime Date { get; set; }
        public virtual string Description { get; set; }
        public virtual IList<ItemPrevia> ListItemPrevia{ get; set; }
    }

public class ItemPrevia
    {
        public virtual int Id { get; set; }
        public virtual string Description { get; set; }  
        public virtual decimal Price { get; set; }
        public virtual Previa Previa { get; set; }
    }

and Mapping:

public class PreviaMap : ClassMap<Previa>
    {
        public PreviaMap()
        {
            Id(f => f.Id)
                .Length(11);
            Map(f => f.Date)
                .Not.Nullable();
            Map(f => f.Description)
                .Not.Nullable();
            HasMany<ItemPrevia>(m => m.ListItemPrevia)
                .Table("ItemPrevia")
                .Inverse()
                .Cascade.AllDeleteOrphan()
                .Not.LazyLoad();
        }
   }
public class ItensPreviaMap : ClassMap<ItemPrevia>
{
    public ItensPreviaMap()
    {
        Id(f => f.Id)
            .Length(11);
        Map(f => f.Description)
                .Not.Nullable();
            Map(f => f.Price)
                .Not.Nullable();
        References(f => f.Previa).Column("IdPrevia").Not.LazyLoad();
     }
 }

In my system i have to register a Previa and after, include some ItemPrevia.
But, i can inform the another Previa and copy your items to the current Previa.

How I could persist the list of the other Previa for the current Previa ?
I Try this:

Previa objPreviaOld = new Previa();
objPreviaOld = PreviaBLL.Search(Convert.ToInt32(txtPreviaOld.Text));
if (objPreviaOld != null) 
{
      foreach (ItemPrevia objItemPrevia in objPreviaOld.ListItemPrevia)
      {
          objItemPrevia.Id = 0;
          objItemPrevia.Previa = objPrevia;
          objPrevia.ListItemPrevia.Add(objItemPrevia);
      }
      PreviaBLL.Alter(objPrevia);
}

But occur this error: identifier of an instance of Domain.Entities.ItemPrevia was altered from 50 to 0

Someone help me ?

Answer 1

as @Merlyn Morgan-Graham said you have to copy the data to new objects.

Previa PreviaOld = PreviaBLL.Search(Convert.ToInt32(txtPreviaOld.Text));
if (objPreviaOld != null) 
{
      foreach (ItemPrevia itemPrevia in objPreviaOld.ListItemPrevia)
      {
          PreviaNew.ListItemPrevia.Add(new ItemPrevia
          {
              Previa = PreviaNew,
              Prop1 = itemPrevia.Prop1,
              Prop2 = itemPrevia.Prop2,
              Prop3 = itemPrevia.Prop3,
              Prop4 = itemPrevia.Prop4,
          });
      }
      PreviaBLL.Alter(PreviaNew);
}