How can I update a detached entity in EF CF multi-tier application?

Question

I'm developing a multi-tier app using EF CF . I managed to delete a detached entity this way:

       public void Delete(DbSet MySet, object Obj)
        {
            MySet.Attach(Obj);
            var Entry = this.Entry(Obj);
            Entry.State = EntityState.Deleted;
            this.SaveChanges();
        }

This method is defined in a class I called Adapter:DbContext. The thing is, when updating, similar code doesn't work:

 public void Update(DbSet MySet, object Obj)             
    {
        MySet.Attach(Obj);
        var Entry = this.Entry(Obj);
        Entry.State = EntityState.Modified;
        this.SaveChanges();
    }

This does not update the database nor throw any exceptions How should I update a detached entity?

Answer 1

Instead of attaching the object, try retrieving the object and updating it - Note: I'm assuming your Id is Obj.Id

public void Update(DbSet MySet, object Obj)             
    {
        var objToUpdate = MySet.Find(Obj.Id);
        if (objToUpdate != null)
        {
        var Entry = this.Entry(objToUpdate );
        Entry.CurrentValues.SetValues(Obj)
        Entry.State = EntityState.Modified;
        this.SaveChanges();
        }
    }