using ( androidhiveEntities db = new androidhiveEntities() )

                {

                    #region 添加

                    //aa a = new aa() { endDate =DateTime.Now,name="张三",doccode="ddoccode ",startDate=DateTime.Now };

                    //db.aa.Add(a);

                    //db.SaveChanges();

                    #endregion

                    #region 修改

                    //修改

                    var a1 = (from u in db.aa where u.id == 25 select u).FirstOrDefault();

                    a1.name = "李晓四";

                    var a = (from u in db.aa where u.id == 27 select u).FirstOrDefault();

                    a.name  = "张晓三";

                    db.SaveChanges();

                    #endregion

                    #region 删除

                    //var a = (from u in db.aa where u.id == 26 select u).First();

                    //db.aa.Remove(a);

                    //db.SaveChanges();

                    #endregion

                }