当IDENTITY_INSERT设置为OFF时，无法在表''中为identity列插入显式值

Question

我尝试使用此代码来逃避错误

  

当IDENTITY_INSERT设置为OFF时，无法在表'T_PreviewDetails'中为identity列插入显式值

但同样的错误也发生在这里。任何解决方案？

context.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[T_PreviewDetails] ON");
context.SaveChanges();
context.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[T_PreviewDetails] OFF");

这是模型类代码：

namespace AP.Model
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel.DataAnnotations;
    using System.ComponentModel.DataAnnotations.Schema;
    using System.Data.Entity.Spatial;

    public partial class T_PreviewDetails
    {
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
        public T_PreviewDetails()
        {
            T_PreviewDetailsComments = new HashSet<T_PreviewDetailsComments>();
        }

        //[DatabaseGenerated(DatabaseGeneratedOption.None)]
        [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
        public int ID { get; set; }

        [StringLength(50)]
        public string Title { get; set; }

        public int? Preview_ID { get; set; }

        public int? SelectionListDetails_ID { get; set; }

        public int? PreviewStatus_ID { get; set; }

        public virtual M_PreviewStatus M_PreviewStatus { get; set; }

        public virtual T_Preview T_Preview { get; set; }

        public virtual T_SelectionListDetails T_SelectionListDetails { get; set; }

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
        public virtual ICollection<T_PreviewDetailsComments> T_PreviewDetailsComments { get; set; }
    }
}

PreviewController.cs包含以下代码：

 using(APM context = new APM())
            {
                T_UserAlbums objAlbum = new T_UserAlbums();
                T_UserAlbumDetails objAlbumDetails = new T_UserAlbumDetails();
                T_SelectionList objSelectList = new T_SelectionList();
                T_SelectionListDetails objSelectListDetails = new T_SelectionListDetails();
                T_Preview objprev = new T_Preview();
                T_PreviewDetails objprevdet = new T_PreviewDetails();



                var lstfile1 = (from s in context.T_OrderDetails
                                join p in context.T_SelectionList on s.SelectionList_ID equals p.ID
                                join q in context.T_SelectionListDetails on p.ID equals q.SelectionList_ID
                                join r in context.T_UserAlbumDetails on q.UserAlbumDetails_ID equals r.ID
                                where s.IsPreviewRequired == 1 && p.User_ID == id
                                select new Preview
                                {
                                    albumid = (int)q.UserAlbumDetails_ID,
                                    selecttionid = (int)q.SelectionList_ID,
                                    p_path = r.PhysicalPath,
                                    v_path = r.VirtualPath,
                                    user = (int)p.User_ID,
                                    orderid = s.ID
                                }).ToList();

                var items = lstfile1.GroupBy(m => m.selecttionid).ToList();

                foreach (var itm in items)
                {
                    objAlbum.Title = "preview";
                    objAlbum.Description = "preview";
                    objAlbum.User_ID = 32;
                    objAlbum.CreatedDate = DateTime.Now;
                    objAlbum.Modifieddate = DateTime.Now;
                    context.T_UserAlbums.Add(objAlbum);            

                    objSelectList.CreatedDate = DateTime.Now;
                    objSelectList.ModifiedDate = DateTime.Now;
                    objSelectList.Title = "Preview";
                    objSelectList.User_ID = id;
                    context.T_SelectionList.Add(objSelectList);

                    objprev.CreatedDate = DateTime.Now;
                    objprev.ModifiedDate = DateTime.Now;
                    objprev.Title = "Preview";
                    objprev.SelectionList_ID = objSelectList.ID;
                    objprev.PreviewStatus_ID = 2;
                    foreach (var im in itm)
                    {
                        objprev.OrderDetails_ID = im.orderid;
                        break;
                    }
                    context.T_Preview.Add(objprev);


                    foreach (var im in itm)
                    {
                        objAlbumDetails.CreatedDate = DateTime.Now;
                        objAlbumDetails.ModifiedDate = DateTime.Now;
                        objAlbumDetails.PhysicalPath = im.p_path;
                        objAlbumDetails.VirtualPath = im.v_path;
                        objAlbumDetails.Title = "Preview";
                        objAlbumDetails.UserAlbum_ID = objAlbum.ID;
                        objAlbumDetails.UploadedType = "Preview";
                        context.T_UserAlbumDetails.Add(objAlbumDetails);

                        objSelectListDetails.CreatedDate = DateTime.Now;
                        objSelectListDetails.ModifiedDate = DateTime.Now;
                        objSelectListDetails.SelectionType = "preview";
                        objSelectListDetails.Title = "preview";
                        objSelectListDetails.UserAlbumDetails_ID = objAlbumDetails.ID;
                        objSelectListDetails.SelectionList_ID = objSelectList.ID;
                        context.T_SelectionListDetails.Add(objSelectListDetails);


                        objprevdet.Title = "preview";
                        objprevdet.Preview_ID = objprev.ID;
                        objprevdet.SelectionListDetails_ID = objSelectListDetails.ID;
                        objprevdet.PreviewStatus_ID = 2;
                        context.T_PreviewDetails.Add(objprevdet);

                            context.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[T_PreviewDetails] OFF");
                            context.SaveChanges();
                            context.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[T_PreviewDetails] ON");


}
}