Entity Framework .NET 中的字段为必填错误

Question

public class Activity
{
    [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int ActivityId { get; set; }
    [ForeignKey("Pet")]
    public int PetId { get; set; }
    public Pet Pet { get; set; }
    public string ActivityName { get; set; }
    
}

在我的 .NET API 项目中，我有一个名为 Activity 的模型，我想发送如下的发布请求：

{
  "activityId": 2,
  "petId": 1,
  "activityName": "Walking"
}

但是我收到这样的错误：

{
  "errors": {
    "Pet": [
      "The Pet field is required."
    ]
  },
  "type": "https://tools.ietf.org/html/rfc9110#section-15.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "00-706cba6aef91222dac75191c63c25a79-a4263882e7c4407b-00"
}

我想要的是在我的宠物模型和表格中将其记录为列表，如下所示，当我输入petId时：

public class Pet
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int PetId { get; set; }
    public string Type { get; set; }
    public string Name { get; set; }
    public List<Activity> Activities { get; set; } = new List<Activity>();
    public List<Food> Foods { get; set; } = new List<Food>();
}

我应该如何纠正模型，我是初学者，非常感谢您的帮助。


I am trying to solve the error I get as I explained in my question.

Answer 1

尝试使用 virtual 关键字在导航属性上启用延迟加载：

public virtual List<Activity> Activities { get; set; } = new List<Activity>();
public virtual List<Food> Foods { get; set; } = new List<Food>();