How to return last Added Value Primary key in Generic Repository in EF4?

i try to write a repository with Ef 4, but there is a problem. i need return last added row in database return id. for exmple: i added Name, SurName but i can not access last added primary id. My Repository is below. my request is secand usage.

using System.Data.Objects;


namespace FlyAnt.DAL.FrameWork.ApplicationDomainModel
{
    public interface IDomainRepository<Tmodel> : IDisposable where Tmodel : class
    {
        IQueryable<Tmodel> Fetch();
        IEnumerable<Tmodel> GetAll();
        IEnumerable<Tmodel> Find(Func<Tmodel, bool> predicate);
        Tmodel Single(Func<Tmodel, bool> predicate);
        Tmodel First(Func<Tmodel, bool> predicate);
        bool Add(Tmodel entity);
        bool Delete(Tmodel entity);
        bool Attach(Tmodel entity);
    }
    public class DomainRepository<TModel> : IDomainRepository<TModel> where TModel : class
    {

        #region IDomainRepository<T> Members
        private ObjectContext _context;
        private IObjectSet<TModel> _objectSet;

        public DomainRepository()
        {
        }

        public DomainRepository(ObjectContext context)
        {

            _context = context;

            _objectSet = _context.CreateObjectSet<TModel>();

        }
. . . . .
. . .
. .
.

  public bool Delete(Func<TModel, bool> predicate)
        {
            IEnumerable<TModel> records = from x in _objectSet.Where<TModel>(predicate) select x;
            foreach (TModel record in records)
                _objectSet.DeleteObject(record);
            return SaveChanges()>0;
        }

        public bool Add(TModel entity)
        {
            if (entity == null)
                throw new ArgumentNullException("entity");
            _objectSet.AddObject(entity);
            return SaveChanges()>0;
        }
...............
..........
......// do someting

SECAND USAGE:how can i return last added or last deleted ID?i try to make below :(

 public bool Delete(Func<TModel, bool> predicate)
        {
            IEnumerable<TModel> records = from x in _objectSet.Where<TModel>(predicate) select x;
            foreach (TModel record in records)
                _objectSet.DeleteObject(record);
            return _objectset.LASTDELETEDPrimaryKEY;
        }

        public bool Add(TModel entity)
        {
            if (entity == null)
                throw n开发者_运维知识库ew ArgumentNullException("entity");
            _objectSet.AddObject(entity);
             return _objectset.LASTADDEDPrimaryKEY;
        }

Best Regards...

soon you do SaveChanges() all will be right there to use.

    public int Add(TModel entity)
    {
        if (entity == null)
            throw new ArgumentNullException("entity");
        _objectSet.AddObject(entity);
        SaveChanges();

        return entity.mytable_id;
    }

if you want to add, let's say values to to tables and one depends on the other, let's assume:

[Table1]     [Table2]
t1_id PK     ts_id PK
t2_id FK     name
name

you can easily:

    public void Add(TModel entity1, TModel entity2)
    {
        if (entity1 == null || entity2 == null)
            throw new ArgumentNullException("entity");

        entity1.Table2 = entity2;

        _objectSet1.AddObject(entity1);
        _objectSet2.AddObject(entity2);

        SaveChanges();
    }