c# - 实体类型 'Access' 需要定义一个主键。如果您打算使用无键实体类型调用 'HasNoKey()'

Question

我有这个 ValueObject :

public class Access : ValueObject<Access>
{
    public string ControllName { get;  set; }
    public string ActionName { get;  set; }

    private Access()
    {

    }
    public Access(string controllerName, string actionName)
    {
        ControllName = controllerName;
        ActionName = actionName;
    }

    protected override IEnumerable<object> GetEqualityComponents()
    {
        yield return ControllName;
        yield return ActionName;
    }
}

这是我的 ValueObject<Access> :

 public abstract class ValueObject<T>
    where T : ValueObject<T>
{
    protected abstract IEnumerable<object> GetEqualityComponents();

    public override bool Equals(object obj)
    {
        var valueObject = obj as T;

        if (ReferenceEquals(valueObject, null))
            return false;

        return IsEquals(valueObject);
    }

    private bool IsEquals(ValueObject<T> other)
    {
        return GetEqualityComponents().SequenceEqual(other.GetEqualityComponents());
    }

    public override int GetHashCode()
    {
        return GetEqualityComponents()
            .Aggregate(1, (current, obj) => current * 23 + (obj?.GetHashCode() ?? 0));
    }

    public static bool operator ==(ValueObject<T> a, ValueObject<T> b)
    {
        if (ReferenceEquals(a, null) && ReferenceEquals(b, null))
            return true;

        if (ReferenceEquals(a, null) || ReferenceEquals(b, null))
            return false;

        return a.Equals(b);
    }

    public static bool operator !=(ValueObject<T> a, ValueObject<T> b)
    {
        return !(a == b);
    }
}

这是我的 DBContext :

 public class StoreAdminPanelGetwayContext : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
=> optionsBuilder.UseSqlServer(@"Server=.; initial catalog=StoreAdminPanelGetway;integrated security=true");

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.ApplyConfigurationsFromAssembly(typeof(Role).Assembly);
    }
    public DbSet<Role> Roles { get; set; }
    public DbSet<AccessLevel> AccessLevels { get; set; }

}

这是我的实体:

  public class AccessLevel : Entity
{
    public int RoleId { get;  set; }
    public Access Access { get;  set; }
    public Role Role { get; set; }
}

但是当我需要时 add-migration initial数据库它告诉我这个错误:

The entity type 'Access' requires a primary key to be defined. If you intended to use a keyless entity type call 'HasNoKey()'.

但是 Access是值对象，它不能有 id 。我怎么解决这个问题 ？？？

Answer 1

EF Core 有 Owned Entity Types 的概念，可用于实现 DDD 值类型。

在 OnModelCreating你会做以下事情:

modelBuilder.Entity<AccessLevel>().OwnsOne(x => x.Access);

这将存储 Access与 AccessLevel 位于同一数据库表中的对象对象，因此不需要主键。