c# - 如何解决 .NET Core with EF Core 必填字段错误？

Question

我有一个 .NET Core (6.0.1) API，它是使用 EF Core (6.0.1) 的数据库优先方法构建的。每当我尝试 POST 到特定实体时，我都会收到实体中导航属性之一的“需要字段”错误。我还有其他几个以类似方式构建的实体，它们似乎工作正常，但这个实体给我带来了问题，我无法弄清楚。有什么想法吗？

来自 DBContext:

    modelBuilder.Entity<InsuranceCompanyStatus>(entity =>
        {
            entity.HasKey(e => e.InsCoStatusId);

            entity.ToTable("InsuranceCompanyStatus");

            entity.Property(e => e.InsCoStatusId).HasColumnName("InsCoStatusID");

            entity.Property(e => e.InsuranceCompanyId).HasColumnName("InsuranceCompanyID");

            entity.Property(e => e.State)
                .HasMaxLength(2)
                .IsUnicode(false)
                .IsFixedLength();

            entity.HasOne(d => d.InsuranceCompany)
                .WithMany(p => p.InsuranceCompanyStatuses)
                .HasForeignKey(d => d.InsuranceCompanyId)
                .HasConstraintName("FK_InsuranceCompanyStatus_InsuranceCompanies");
        });

脚手架模型:

    public partial class InsuranceCompanyStatus
    {
      public int InsCoStatusId { get; set; }
      public Guid InsuranceCompanyId { get; set; }
      public string State { get; set; } = null!;
      public bool Admitted { get; set; }
      public bool? Approved { get; set; }

      public virtual InsuranceCompany InsuranceCompany { get; set; } = null!;
    }

来自尝试的 POST 正文的 JSON:

    {
     "insuranceCompanyId": "caa3e956-a3be-4670-83e3-53a6ec47731e",
     "state": "AL",
     "admitted": true,
     "approved": true
    }

错误响应状态为400:

    {
     "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
     "title": "One or more validation errors occurred.",
     "status": 400,
     "traceId": "00-cf1de6fe8e4fb67a04ff7d4c8b6a1c68-f426059123424d72-00",
     "errors": {
        "InsuranceCompany": [
        "The InsuranceCompany field is required."
     ]
    }
    }

Answer 1

您必须创建可为空的 InsuranceCompanyId

public partial class InsuranceCompanyStatus
{
    public int InsCoStatusId { get; set; }
    
    ....
    public Guid? InsuranceCompanyId { get; set; }
    
    public virtual InsuranceCompany InsuranceCompany { get; set; }  // = null!; you don't need it , it is null by default
}

它通常有效，但如果仍然无效，您可以在 fluent appi 中显式添加它

 modelBuilder.Entity<InsuranceCompanyStatus>(entity =>
 {
   .....  
   entity.Property(e => e.InsuranceCompanyId).IsOptional();