Asp.net mvc 保存数据时出现System.data.entity.validation.DbEntityValdationException错误

这是我的控制器

public JsonResult SaveBillingSystemParameters(BillingSystemParameters model)
        {
            var id = -1;
            //Initialize the newId variable 
            var userId = Helpers.GetLoggedInUserId();
            var currentDate = Helpers.GetInvariantCultureDateTime();
            var defaultCorporateId = Helpers.GetSysAdminCorporateID();

            //Check if Model is not null
            if (model != null)
            {
                using (var bal = new BillingSystemParametersBal())
                {
                    model.CorporateId = defaultCorporateId;
                    if (model.Id > 0)
                    {
                        model.ModifiedBy = userId;
                        model.ModifiedDate = currentDate;
                    }
                    else
                    {
                        model.CreatedBy = userId;
                        model.CreatedDate = currentDate;
                        model.CorporateId = Helpers.GetSysAdminCorporateID();
                    }

                    //Call the AddBillingSystemParameters Method to Add / Update current BillingSystemParameters
                    id = bal.SaveBillingSystemParameters(model);
                }
            }
            return Json(id);
        }

//Bal class

public int SaveBillingSystemParameters(BillingSystemParameters model)
        {
            using (var rep = UnitOfWork.BillingSystemParametersRepository)
            {
                if (model.Id > 0)
                {
                    var current = rep.GetSingle(model.Id);
                    model.CreatedBy = current.CreatedBy;
                    model.CreatedDate = current.CreatedDate;
                    rep.UpdateEntity(model, model.Id);
                }
                else
                    rep.Create(model);

                return model.Id;
            }
        }

我得到以下错误

---

按照异常消息所述，检查EntityValidationError 此异常通常意味着您试图打破一些约束，如varchar field width

---

如果浏览此参数，您将获得有关尝试阻止的Constraint SaveChanges（）类型的更多详细信息 此异常通常意味着您试图打破一些约束，如varchar field width 如果浏览此参数，您将获得有关尝试制动的Constraint SaveChanges（）类型的更多详细信息