Asp.net mvc Sql事务是完全异常

我有一个奇怪的问题。所有文档都指出，在提交事务之前必须首先调用SaveChanges方法，但在我的情况下，如果这样做，则会引发异常。 通过在SaveChanges之前调用Commit，我可以避免Sql事务完全异常

    [HttpPost]
    public ActionResult ajax_SaveScreentest(string ScreenTestResult = "")
    {

        var shops = from m in db_emp.WorkLocations
                    where m.LocationType == "Shop"
                    select m;       

        db.Database.Connection.Open();
        using (var dbtran = db.Database.Connection.BeginTransaction())
        {
            try
            {
                if (ScreenTestResult != "")
                {

                    var sc = js.Deserialize<ScreenTest>(ScreenTestResult);
                    AppFieldValidator.Validate(sc);
                    db.Entry(sc).State = System.Data.EntityState.Added;
                    dbtran.Commit(); //needs to commit first before savechanges otherwise The sql                transaction is completed exception will occur
                    db.SaveChanges();


                    foreach (var obj in shops)
                    {
                        ScreenShop ss = new ScreenShop();
                        ss.ScreenID = sc.ID;
                        ss.ShopID = obj.WorkLocationID;
                        ss.ScreenStatus = "Outstanding";
                        ss.ScreenDateSubmitted = null;
                        db.Entry(ss).State = System.Data.EntityState.Added;
                    }

                    db.SaveChanges();

                    return Json(new { success = true, message = "" });
                }
                return Json(new { success = false, message = "Screen Test is not supplied" });
            }

            catch (Exception e)
            {
                dbtran.Rollback();
                if (e.Message.IndexOf("Validation failed for one or more entities.") != -1)
                    return Json(new { success = false, message = "One of the entries you made is      ether too long or unacceptable!" });
                return Json(new { success = false, message = e.InnerException != null ?    e.InnerException.Message : e.Message });
            }
            finally
            {
                db.Dispose();
            }
        }

---

nvm解决了这个错误。在调用Commit之前，我首先添加了db.SaveChanges方法