Biegral Blog

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

            List<string> listID = new List<string>();
            for (int i = 0; i < 1000; i++)
            {
                listID.Add("b" + i.ToString());
            }

            DateTime bt = DateTime.Now;



            using (MK_UboxChsEntities ent = new MK_UboxChsEntities())
            {
                //list = ent.USER_TBL.Where(rec => listID.Contains(rec.USER_NAME)).ToList();// 300多ms

                var v1 = listID.Join(ent.USER_TBL, u => u, p => p.USER_NAME, (o, p) => p); //18ms

                list = v1.ToList();

            }

            DateTime et = DateTime.Now;

            MessageBox.Show((et - bt).Milliseconds.ToString());