3

虽然我在这里关注了这篇文章，但我一直收到错误消息

检测到类型为“...”的属性“...”的自引用循环。路径“[4]....[0]”。

我已将此添加到我的Startup.cs：

services.AddMvc()
    .AddJsonOptions(opt => 
        opt.SerializerSettings.ReferenceLoopHandling = 
            ReferenceLoopHandling.Ignore
    );

还有什么可能导致参考循环错误？

编辑：在评论中回答问题......受影响的课程是：

public partial class GuidingSymptom
    {
        public GuidingSymptom()
        {
            VideosGuidingSymptoms = new HashSet<VideosGuidingSymptoms>();
        }
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }
        [MaxLength(70)]
        [Required]
        public string Name { get; set; }
        public string Description { get; set; }

        public int SeverityId { get; set; }
        public int? DiagnoseId { get; set; }

        [InverseProperty("GuidingSymptom")]
        public virtual ICollection<VideosGuidingSymptoms> VideosGuidingSymptoms { get; set; }
        [ForeignKey("DiagnoseId")]
        [InverseProperty("GuidingSymptom")]
        public virtual Diagnose Diagnose { get; set; }
        [ForeignKey("SeverityId")]
        [InverseProperty("GuidingSymptom")]
        public virtual GuidingSymptomSeverity Severity { get; set; }
    }

public partial class VideosGuidingSymptoms
{
    public int VideoId { get; set; }
    public int GuidingSymptomId { get; set; }

    [ForeignKey("GuidingSymptomId")]
    [InverseProperty("VideosGuidingSymptoms")]
    public virtual GuidingSymptom GuidingSymptom { get; set; }
    [ForeignKey("VideoId")]
    [InverseProperty("VideosGuidingSymptoms")]
    public virtual Video Video { get; set; }
}
4

2 回答 2

5

我找到了要添加的解决方案

[JsonIgnore]

注释到受影响的属性。但是，我希望在使用时不需要这样做ReferenceLoopHandling.Ignore

于 2017-05-30T19:22:15.463 回答
2

一些序列化框架不允许这样的循环。例如，如果遇到循环，Json.NET 将抛出以下异常。

Newtonsoft.Json.JsonSerializationException: Self referencing loop detected for property 'Blog' with type 'MyApplication.Models.Blog'.

如果您使用的是 ASP.NET Core，则可以将 Json.NET 配置为忽略它在对象图中找到的循环。这是在 中的ConfigureServices(...)方法中完成的Startup.cs。

public void ConfigureServices(IServiceCollection services)
{
    ...

    services.AddMvc()
        .AddJsonOptions(
            options => options.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore
        );

    ...
}

https://docs.microsoft.com/en-us/ef/core/querying/related-data

于 2019-01-15T09:11:41.823 回答