无法在对象“dbo.FeedBack”中插入重复键

Question

{“违反主键约束‘PK_ been’。不能在对象'dbo.FeedBack‘中插入重复键。重复的键值是(0).\r\nThe语句已终止。”}

public int InsertFeedBack(FeedBack fb)
    {
        db.FeedBacks.Add(fb);
        db.SaveChanges();

        return fb.ID;
    }

public JsonResult Send(string name, string mobile, string address, string email, string content)
    {
        var feedback = new FeedBack();
        feedback.Name = name;
        feedback.Email = email;
        feedback.CreatDate = DateTime.Now;
        feedback.Phone = mobile;
        feedback.Content = content;
        feedback.Address = address;

        var id = new LHeDAO().InsertFeedBack(feedback);
        if (id > 0)
        {
            return Json(new
            {
                status = true
            });
            //send mail
        }

        else
            return Json(new
            {
                status = false
            });
    }

public partial class FeedBack
{
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int ID { get; set; }

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

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

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

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

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

    public DateTime? CreatDate { get; set; }

    public bool? status { get; set; }
}

Answer 1

我想你的身份证需要

 [DatabaseGenerated(DatabaseGeneratedOption.Identity)]

并确保ID设置为DB中的identity列。

Answer 2

要么使用[DatabaseGenerated(DatabaseGeneratedOption.Identity)]自动生成ID，要么自己生成ID (必须是唯一的)。

Answer 3

您提供的代码示例没有显示ID的任何初始化

    var feedback = new FeedBack();
    feedback.Name = name;
    feedback.Email = email;
    feedback.CreatDate = DateTime.Now;
    feedback.Phone = mobile;
    feedback.Content = content;
    feedback.Address = address;

    var id = new LHeDAO().InsertFeedBack(feedback);**

并且明确声明数据库不应该生成它：

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

因此，默认情况下，ID被初始化为0，数据库在尝试插入时返回该错误，因为表中已经有ID为0的行。要解决这个问题，您需要允许数据库为ID生成值，或者在尝试执行插入之前使用唯一值初始化ID。