c# - 当 IDENTITY_INSERT 设置为 OFF 时，无法为标识列插入显式值

Question

我正在尝试设置一个复合主键，第二个键是年份。

我已经在表创建和构造函数中设置为自动生成字段，但我仍然收到此错误:

Cannot insert explicit value for identity column in table Volunteer when IDENTITY_INSERT is set to OFF.

代码和设置的所有三个部分如下。

  [Table("Volunteer")]
    public class Volunteer
    {

        [Key][Column(Order = 0)]
        public int Id { get; set; }

        [DisplayName("First Name")]
        public string FirstName { get; set; }

        [DisplayName("Last Name")]
        public string LastName { get; set; }

        [DisplayName("Team Mentored")]
        public string TeamMentored { get; set; }


        [Key][Column(Order = 1)] [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public DateTime Year { get; set; }
        public string TableNumber { get; set; }
        public int OfficeId { get; set; }
        public string Image { get; set; }


    }

CREATE TABLE [dbo].[Volunteer](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [FirstName] [nvarchar](255) NULL,
    [LastName] [nvarchar](255) NULL,
    [TeamMentored] [nvarchar](255) NULL,
    [Year] [date] DEFAULT(getdate()) NOT NULL,
    [TableNumber] [nvarchar](50) NULL,
    [OfficeId] [int] NOT NULL,
    [Image] [nvarchar](max) NULL
 )


public ActionResult Create([Bind(Include = "FirstName,LastName,TeamMentored,TableNumber,OfficeId,Image")] Volunteer volunteer)
        {
            try
            {

                if (ModelState.IsValid)
                {
                    db.Volunteers.Add(volunteer);
                    db.SaveChanges();

                    ModelState.Clear();
                } 

                // TODO: Add insert logic here

                return RedirectToAction("Index");
            }
            catch
            {
                ModelState.AddModelError("", "DB Update Failed!"); 
            }

            return View();
        }

Answer 1

尝试在“Id”属性上使用属性 [DatabaseGenerated(DatabaseGeneratedOption.Identity)]。如果那不行，是否可以发布分配代码并保存？