Results View = Cannot evaluate expression because a thread is stopped at a point where garbage collection is impossible, possibly because the code is optimized.

var st1 = from p in context.pic_product
                                    where p.product_id == ert.key
                                    select new
                                    {
                                        p.part_number,
                                        p.part_description,
                                    };

                 var st = st1.SingleOrDefault();
                          if (st1 != null)
                          {
                              var attr = new AttributeDTO {
                                  AttrName = st.part_number,
                                  temp = st.part_description };
                              lst1.Add(attr);
                          }
                   });