Question

我收到了错误消息。我有2张桌子DonHang，Kho。 DonHang链接到Kho（DonHang.kid - ＆gt; Kho.id）我首先使用Visual Studio 2017中的数据库创建了模型DonHang，Kho，类ShopDbContext。我在我的项目中创建了控制器Home有动作Create（使用向表DonHang添加数据）。但是，当我使用此操作时，网站会自动将数据添加到表格Kho并为tabe DonHang分配新ID，尽管在项目中没有动作创建Kho。

我将项目代码发送给所有人谢谢！

模特DonHang

[Table("DonHang")]
public partial class DonHang
{
    public int id { get; set; }

    public int? uid { get; set; }

    public int? kid { get; set; }

    public int? soluong { get; set; }

    public DateTime? ngayxuat { get; set; }

    public int? khachhang { get; set; }

    public int? thanhtoan { get; set; }

    public int? no { get; set; }

    public string ghichu { get; set; }

    public int? thanhtien { get; set; }

    public virtual KhachHang KhachHang1 { get; set; }

    public virtual Kho Kho { get; set; }

    public virtual TaiKhoan TaiKhoan { get; set; }
}

模特Kho

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

    public int id { get; set; }

    public int? uid { get; set; }

    public int? soluong { get; set; }

    public int? gianhap { get; set; }

    public int? giaxuat { get; set; }

    public DateTime? ngaynhap { get; set; }

    [StringLength(250)]
    public string tensanpham { get; set; }

    public string mota { get; set; }

    public int? phanloai { get; set; }

    public int? tinhtrang { get; set; }

    [StringLength(250)]
    public string donvi { get; set; }

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

    public virtual TaiKhoan TaiKhoan { get; set; }
}

ShopDbContex

public partial class ShopDbContext : DbContext
{
    public ShopDbContext()
        : base("name=ShopDbContext")
    {
    }

    public virtual DbSet<DonHang> DonHangs { get; set; }
    public virtual DbSet<KhachHang> KhachHangs { get; set; }
    public virtual DbSet<Kho> Khoes { get; set; }
    public virtual DbSet<TaiKhoan> TaiKhoans { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<KhachHang>()
            .HasMany(e => e.DonHangs)
            .WithOptional(e => e.KhachHang1)
            .HasForeignKey(e => e.khachhang);

        modelBuilder.Entity<Kho>()
            .HasMany(e => e.DonHangs)
            .WithOptional(e => e.Kho)
            .HasForeignKey(e => e.kid);

        modelBuilder.Entity<TaiKhoan>()
            .HasMany(e => e.DonHangs)
            .WithOptional(e => e.TaiKhoan)
            .HasForeignKey(e => e.uid);

        modelBuilder.Entity<TaiKhoan>()
            .HasMany(e => e.KhachHangs)
            .WithOptional(e => e.TaiKhoan)
            .HasForeignKey(e => e.uid);

        modelBuilder.Entity<TaiKhoan>()
            .HasMany(e => e.Khoes)
            .WithOptional(e => e.TaiKhoan)
            .HasForeignKey(e => e.uid);
    }
}

控制器

[HttpPost]
    public ActionResult Create(DonHang dh)
    {
        if (ModelState.IsValid)
        {
            try
            {
                dh.uid = Convert.ToInt32(Session["UID"]);
                dh.khachhang = 3;
                dh.ghichu = "";
                dh.kid = 29;
                dh.ngayxuat = DateTime.Now;
                db.DonHangs.Add(dh);
                db.SaveChanges();
                TempData["Alert"] = "<div class='alert alert-success'>Thêm khách hàng thành công.</div>";
                return RedirectToAction("Index");
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                throw;
            }
        }
        return View();
    }

查看 View

Answer 1

根据您的帖子，如下：

[Table("DonHang")]
public partial class DonHang
{
    ...
    public int? kid { get; set; }
    ...
    public virtual Kho Kho { get; set; }

}

DonHang可以有0或1 Kho。换句话说，DonHang可以在没有Kho的情况下存在。因此，在您的控制器“创建操作”中，您可以注释掉或删除以下行，并查看是否仍会在数据库中创建Kho：

[HttpPost]
public ActionResult Create(DonHang dh)
{
    if (ModelState.IsValid)
    {
        try
        {
            ...
            //dh.kid = 29;    //Comment out or remove this line
            ...
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }
    return View();
}

您分配给dh.Kid的除null之外的任何值都必须在Kho表中具有相应的k.Id。如果没有带有Id 29的Kho，则无法将值29分配给dh.Kid。我怀疑当您尝试插入新的DonHang时，EF会自动创建一个ID为29的Kho。这是有效的，因为除了Id PK之外，Kho表的所有字段都可以为空。

错误！在MVC 5中自动添加数据在操作中创建

1 个答案: