第三节:EF

1.删除要进行判空

public ActionResult DelClassMethod(string gId)
        {
            //根据gId查询对应条目
            var grade = oc.BllSession.IGradeBLL.Entities.Where(a => a.gId == gId).FirstOrDefault();
            var stuInfo = oc.BllSession.IStuInfoBLL.Entities.Where(b => b.gId == gId).FirstOrDefault();
            //进行删除
            if (stuInfo != null)
            {
                oc.BllSession.IStuInfoBLL.DelNo(stuInfo);
            }
            if (grade != null)
            {
                oc.BllSession.IGradeBLL.DelNo(grade);
            }


            int result = oc.BllSession.IGradeBLL.SaveChange();
            if (result > 0)
            {
                return Content("ok");
            }
            else
            {
                return Content("error");
            }
        }

2.批量删除

        public ActionResult DelStuMethod(string idsStr)
        {
            //进行字符串拆分
            string[] str = idsStr.Split(new char[] { ',' });
            int[] str_int = Array.ConvertAll(str, int.Parse);
            List<int> stuIdList = str_int.ToList();
            var stuList = oc.BllSession.IStuInfoBLL.Entities.Where(a => stuIdList.Contains(a.sId)).ToList();
            //删除操作
            foreach (var item in stuList)
            {
                oc.BllSession.IStuInfoBLL.DelNo(item);
            }
            int result = oc.BllSession.IGradeBLL.SaveChange();

            //int result = oc.BllSession.IStuInfoBLL.DelBy(a => stuIdList.Contains(a.sId));
            if (result > 0)
            {
                return Content("ok");
            }
            else
            {
                return Content("error");
            }
        }