如何通过Postman创建Clothes对象？解决必填字段报错问题

我在通过Postman创建Clothes对象时，系统提示Designer_Clothes和FashionHouse字段为必填项，请求无法成功执行。

实体模型代码 #

Clothes类：

public class Clothes:IEntityBase
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public double Price { get; set; }
    public string ImageUrl { get; set; }
    public ClothesCategory ClothesCategory { get; set; }

    public List<Designer_Clothes> Designer_Clothes { get; set; }

    public int FashionHouseId { get; set; }
    [ForeignKey("FashionHouseId")]
    public FashionHouse FashionHouse { get; set; }
}

Designer类：

public class Designer:IEntityBase
{
    [HiddenInput]
    [Key]
    public int Id { get; set; }
    [Display(Name = "Profile Picture")]
    [Required(ErrorMessage ="Profile picture is required")]
    public string ProfilePictureUrl { get; set; }
    [Display(Name = "Full Name")]
    [Required(ErrorMessage ="Full name is required")]
    [StringLength(25, MinimumLength =3,ErrorMessage ="Full name must be between 3 and 25 chars")]
    public string FullName { get; set; }
    [Display(Name = "Bio")]
    [Required(ErrorMessage ="Biography is required")]
    public string Bio { get; set; }
    public List<Designer_Clothes>? Designer_Clothes { get; set; }
}

Designer_Clothes类：

public class Designer_Clothes
{
    public int ClothesId { get; set; }
    public Clothes Clothes { get; set; }
    public int DesignerId { get; set; }
    public Designer Designer { get; set; }
}

FashionHouse类：

public class FashionHouse:IEntityBase
{
    [Key]
    public int Id { get; set; }
    [Display(Name ="Profile picture")]
    [Required(ErrorMessage ="Profile picture is required")]
    public string ProfilePictureUrl { get; set; }
    [Display(Name ="Full Name")]
    [StringLength(50,MinimumLength =3,ErrorMessage ="Full name must be between 3 and 50 chars")]
    [Required(ErrorMessage = "Full name is required")]
    public string FullName { get; set; }
    [Display(Name = "Bio")]
    [Required(ErrorMessage = "Biography is required")]
    public string Bio { get; set; }

    public List<Clothes>? Clothes { get; set; }
}

控制器Post方法 #

[HttpPost]
public async Task<IActionResult> Create([FromBody] Clothes clothes)
{
    if (!ModelState.IsValid)
    {
        return BadRequest();
    }
    await _service.AddAsync(clothes);
    return Created($"/api/book/{clothes.Id}", clothes);
}

提交的JSON请求体 #

{
    "name": "Second item ",
    "description": "Description of second item test",
    "price": 50,
    "imageUrl": "sdfdsfsdfsf",
    "clothesCategory": 3,
    "designer_Clothes": [{
        "ClothesId":1,
        "DesignerId":2
        
    }],
    "fashionHouseId": 2,
    "fashionHouse": {
        "Bio":"TEST",
        "FullName":"TESTE",
        "ProfilePictureUrl":"ASdASd"
    }
}

1. 修复实体模型的可空性问题 #

EF Core默认会将未标记为可空的引用类型视为必填项，导致模型验证失败。修改Clothes类，将关联属性标记为可空：

public class Clothes:IEntityBase
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public double Price { get; set; }
    public string ImageUrl { get; set; }
    public ClothesCategory ClothesCategory { get; set; }

    // 标记为可空集合
    public List<Designer_Clothes>? Designer_Clothes { get; set; }

    public int FashionHouseId { get; set; }
    [ForeignKey("FashionHouseId")]
    // 标记导航属性为可空
    public FashionHouse? FashionHouse { get; set; }
}

2. 调整请求体，移除冗余数据 #

• 已传递fashionHouseId:2，无需再传递完整的fashionHouse对象，否则EF会尝试创建新的FashionHouse实例，同时触发该对象的必填字段验证。
• 新创建的Clothes还未生成ID，不需要手动指定Designer_Clothes中的ClothesId。

修改后的请求体：

{
    "name": "Second item",
    "description": "Description of second item test",
    "price": 50,
    "imageUrl": "sdfdsfsdfsf",
    "clothesCategory": 3,
    "designer_Clothes": [{
        "DesignerId": 2
    }],
    "fashionHouseId": 2
}

3. 配置EF Core关联关系 #

确保DbContext中正确配置Designer_Clothes的复合主键和关联规则，避免数据操作异常：

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    // 配置复合主键
    modelBuilder.Entity<Designer_Clothes>()
        .HasKey(dc => new { dc.ClothesId, dc.DesignerId });

    // 配置Clothes与Designer_Clothes的关联
    modelBuilder.Entity<Designer_Clothes>()
        .HasOne(dc => dc.Clothes)
        .WithMany(c => c.Designer_Clothes)
        .HasForeignKey(dc => dc.ClothesId);

    // 配置Designer与Designer_Clothes的关联
    modelBuilder.Entity<Designer_Clothes>()
        .HasOne(dc => dc.Designer)
        .WithMany(d => d.Designer_Clothes)
        .HasForeignKey(dc => dc.DesignerId);
}

4. 返回具体验证错误排查问题 #

修改控制器方法，返回详细的模型验证错误，方便定位问题：

[HttpPost]
public async Task<IActionResult> Create([FromBody] Clothes clothes)
{
    if (!ModelState.IsValid)
    {
        // 返回具体错误信息
        return BadRequest(ModelState);
    }
    await _service.AddAsync(clothes);
    return Created($"/api/clothes/{clothes.Id}", clothes);
}

内容的提问来源于stack exchange，提问作者Ptrk12