//读取当前对象的属性值 public void EFReadEnitityInfo() { var result = learndb.ustudent.Where(o => o.gid == "02").First(); result.ssexy = "无"; var originalValue = learndb.Entry(result).Property(c => c.ssexy).OriginalValue; var currentValue = learndb.Entry(result).Property(c => c.ssexy).CurrentValue; var databaseValue = learndb.Entry(result).GetDatabaseValues().GetValue <string>("ssexy"); Console.WriteLine("初始值为:{0},当前值为:{1},数据库中值为:{2}", originalValue, currentValue, databaseValue); }
// @see search "EF模型增删改查" private void button_delete_Click(object sender, EventArgs e) { //lqRecCustTransDataContext sail_heEntities db = new sail_heEntities(); ustudent delete = new ustudent(); delete.sid = int.Parse(studentS[listBox_main.SelectedIndex].getStuId()); db.Entry(delete).State = System.Data.Entity.EntityState.Deleted; studentS.RemoveAt(listBox_main.SelectedIndex); Clear(); studentS.ForEach(ele => WriteLine(ele.tabString())); db.SaveChanges(); /* * var q = (from c in db.ustudent * where c.sid == tb_UserInf.CreateUser && c.AutoId == iAid * select c).First(); * db.ustudent.DeleteOnSubmit(q); * db.ustudent.delete * * var q2 = db.ustudent.First(c => c.AutoId == iAid && c.CreateUser == tb_UserInf.CreateUser); * db.ustudent.DeleteOnSubmit(q2); * * @see https://docs.microsoft.com/zh-cn/dotnet/framework/data/adonet/sql/linq/how-to-delete-rows-from-the-database * // Query the database for the rows to be deleted. * var deleteOrderDetails = * from details in db.ustudent * where details.sid == 11000 * select details; * * foreach (var detail in deleteOrderDetails) * { * db.ustudent.DeleteOnSubmit(detail); * } * * try * { * db.SubmitChanges(); * } * catch (Exception e) * { * Console.WriteLine(e); * // Provide for exceptions. * }*/ }