public bool DelCategory(int id)

        {

            bool ret = false;

            try

            {               

                List<int> list = new List<int>();

                if (!list.Contains(id))

                {

                    list.Add(id);

                }

                list = GetKey(id, list);              



                    var x = from s in dbLinq.MaterialAttributes where list.Contains(s.ID) select s ;

                    foreach (var n in x )

                    {

                        dbLinq.MaterialAttributes.DeleteOnSubmit(n);

                        try

                        {

                            dbLinq.SubmitChanges();

                        }

                        catch (System.Data.Linq.ChangeConflictException)

                        {

                          foreach (System.Data.Linq.ObjectChangeConflict occ in dbLinq.ChangeConflicts)

                        {



                        //以下是解决冲突的三种方法，选一种即可



                        // 使用当前数据库中的值，覆盖Linq缓存中实体对象的值

                       // occ.Resolve(System.Data.Linq.RefreshMode.OverwriteCurrentValues);