因为另一个相同类型的实体已经具有相同的主键值而失败

Question

如何修复错误..

更新记录时出现以下错误:

显示错误: {"Attaching an entity of type 'DomainClass.WorkshopReport' failed because another entity of the same type already has the same primary key value. This can happen when using the 'Attach' method or setting the state of an entity to 'Unchanged' or 'Modified' if any entities in the graph have conflicting key values. This may be because some entities are new and have not yet received database-generated key values. In this case use the 'Add' method or the 'Added' entity state to track the graph and then set the state of non-new entities to 'Unchanged' or 'Modified' as appropriate."}

域类:

namespace DomainClass
{
    public class WorkshopReport
    {
        public int Id { set; get; }
        public int UserId { set; get; }
        public int? ManagerIdConfirm { set; get; }
        public bool? ManagerConfirmState { set; get; }
        public DateTime? ManagerConfirmDateTime { set; get; }
        public int? SuperviderIdConfirm { set; get; }
        public bool? SuperviderConfirmState { set; get; }
        public DateTime? SuperviderConfirmDateTime { set; get; }
        public string ReportNumber { set; get; }
        public string Shift { set; get; }
        public string ShiftWork { set; get; }
        public DateTime ShiftDate { set; get; }
        public string ShiftPersennel { set; get; }
        public string Type { set; get; }
        public DateTime SubmitDateTime { set; get; }
    }
}

接口仓库：

namespace InterfaceRepository
{
    public interface IWorkshopReportRepository
    {
        IQueryable<WorkshopReport> Get();
        bool Save();
        bool Add(WorkshopReport newValue);
        bool Delete(WorkshopReport deleted);
        bool Edit(WorkshopReport updated);
        IQueryable<WorkshopReport> FindById(int Id);
        IQueryable<WorkshopReport> Search(string ReportNumber);
    }
}

存储库层：

 namespace RepositoryLayer
{
    public class WorkshopReportRepository:IWorkshopReportRepository
    {
        public CMSDataContext _ctx;
        public WorkshopReportRepository(CMSDataContext ctx)
        {
            _ctx = ctx;
        }
        public IQueryable<WorkshopReport> Get()
        {
            return _ctx.WorkshopReports;
        }

        public bool Save()
        {
            try
            {
                return _ctx.SaveChanges() > 0;
            }
            catch (Exception ex)
            {
                // TODO log this error
                return false;
            }
        }
        public bool Add(WorkshopReport newValue)
        {
            try
            {
                _ctx.WorkshopReports.Add(newValue);
                return true;
            }
            catch (Exception ex)
            {
                // TODO log this error
                return false;
            }
        }

        public bool Delete(WorkshopReport deleted)
        {

            try
            {
                _ctx.WorkshopReports.Remove(deleted);
                return true;
            }
            catch (Exception ex)
            {
                // TODO log this error
                return false;
            }
        }


        public bool Edit(WorkshopReport updated)
        {
            try
            {
                _ctx.Entry(updated).State = System.Data.Entity.EntityState.Modified;
                return true;
            }
            catch (Exception ex)
            {
                // TODO log this error
                return false;
            }
        }

        public IQueryable<WorkshopReport> Search(string Value)
        {
            return _ctx.WorkshopReports.Where(i => i.ReportNumber.Contains(Value));
        }

        public IQueryable<WorkshopReport> FindById(int Id)
        {
            return _ctx.WorkshopReports.Where(i => i.Id == Id);
        }
    }
}

车间主管:

public ActionResult Edit(WorkshopReport value, FormCollection formvalue)
        {
            try
            {

                    value.ShiftDate =
                        _calenderRepository.ConvertPersianToEnglishFormat(formvalue["ShiftDate"].ToString());
                    value.SubmitDateTime=DateTime.Now;
                    value.Type = internalType;
                    value.UserId= _userRepository.FindByEmail(User.Identity.Name).Id;
                    if (_workshopReportRepository.Edit(value))
                    {
                        _workshopReportRepository.Save();
                        TempData["Success"] = "Updated";
                    }

            }
            catch (Exception)
            {
                TempData["Error"] = "Try again...";
            }
            return RedirectToAction("Index", "WorkshopReport", new { type = internalType });

在存储库层显示错误：

- Mehrdad Ghaffari

---

请指导我。 - Mehrdad Ghaffari

如果尚未将“Entry（更新）”附加到上下文中，则会将“更新”附加到上下文中。此对象来自何处？它的PK值是多少，上下文生命周期是多久（即跟踪哪些对象）？ - DevilSuichiro

Answer 1

问题是通过这种方式解决的。

public bool Edit(WorkshopReport updated)
        {
            try
            {
                var local = _ctx.Set<WorkshopReport>()
                    .Local
                    .FirstOrDefault(f => f.Id == updated.Id);
                if (local != null)
                {
                    _ctx.Entry(local).State = EntityState.Detached;
                }
                _ctx.Entry(updated).State = System.Data.Entity.EntityState.Modified;
                return true;
            }
            catch (Exception ex)
            {
                // TODO log this error
                return false;
            }
        }

- Mehrdad Ghaffari

---

这对我解决了问题！ 同样适用于删除。 - MichaelEr