实体类型List需要定义主键

Question

我正在使用 .NEW 5 和 Entity Framework 作为 ORM。我想使用代码优先的数据库方法。

我有 2 个实体 classes:

public class PurnchaseOrderItem
{
    public int Id { get; set; }
    public string Name { get; set; }
    public double Price { get; set; }

    [ForeignKey("PurnchaseOrder")]
    public int PurnchaseOrderId { get; set; }
    public PurnchaseOrder PurnchaseOrder { get; set; }
}

public class PurnchaseOrder
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime  CreationDate { get; set; }
    public List<PurnchaseOrderItem> PurnchaseOrderItems { get; set; }

    [NotMapped]
    public double TotalPrice
    {
        get
        {
            return PurnchaseOrderItems.Sum(x => x.Price);
        }
    }
}

但是当我尝试添加新的迁移时，我得到这样的错误：

The entity type 'List' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. For more information on keyless entity types, see https://go.microsoft.com/fwlink/?linkid=2141943.

还有我的数据库上下文 class:

public class ItemsAppDbContext : DbContext
{
    public ItemsAppDbContext(DbContextOptions options) : base(options)
    {
    }

    public DbSet<AppUser> Users { get; set; }
    public DbSet<PurnchaseOrderItem> PurnchaseOrderItems { get; set; }
    public DbSet<PurnchaseOrder> PurnchaseOrders { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<PurnchaseOrder>()
        .HasOne(p => p.PurnchaseOrderItems)
        .WithMany()
        .OnDelete(DeleteBehavior.Cascade);
    }
}

Answer 1

更新 ItemsAppDbContext 中的以下代码

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<PurnchaseOrder>()
    .HasMany(p => p.PurnchaseOrderItems)
    .WithOne(g => g.PurnchaseOrder).HasForeignKey(s=>s.PurnchaseOrderId)
    .OnDelete(DeleteBehavior.Cascade);
}

阅读 this 了解更多。

实体类型List需要定义主键

The entity type List requires a primary key to be defined

c#

asp.net

entity-framework

asp.net-core