使用InverseProperty时，Entity Framework Core模型中的自引用循环

Question

I have the following models:

  public class MasterData
  {
    [Key]
    public Guid ID { get; set; }

    [Required]
    public string Name { get; set; } 

    [InverseProperty(nameof(DetailData.MasterData))]
    public List<Detaildata> Details { get; set; }
  }

  public class DetailData
  {
    [Key]
    public Guid ID { get; set; }

    [Required]
    public string Name { get; set; }

    [InverseProperty(nameof(ChildData.DetailData))]
    public List<ChildData> Children { get; set; }

    public Guid MasterDataID { get; set; }

    [ForeignKey(nameof(MasterDataID))]
    public MasterData MasterData { get; set; }
  }


  public class ChildData
  {
    [Key]
    public Guid ID { get; set; }

    [Required]
    public string Name { get; set; }

    public Guid SectionID { get; set; }

    [ForeignKey(nameof(SectionID))]
    public Section ChildSection { get; set; }

    public Guid DetailDataID { get; set; }

    [ForeignKey(nameof(DetailDataID))]
    public DetailData DetailData { get; set; }
  }

To make sure that the migration is well generated and to avoid shadow properties , I add the InverseProperty attribute to define both ends of the relationship.

However, when I try to serialize the instances, I get the following exception:

Self referencing loop detected for property 'DetailData' with type 'Models.DetailData'. Path 'Value.Item1.Details[0].Children[0]'.

Well, obviously it is a self referencing loop, as MasterData has a DetailData that has a MasterData navigation object back - as it should be in a navigational relationship.

Unfortunately, I need to serialize these objects.

A workaround would be to mark the InverseProperty properties with the JsonIgnore attribute, but I'm not sure what it would cause in the deserializing side of the project.

What should I do to avoid the self referencing loop without ignoring the navigation properties?

Answer 1

You could ignore circular reference globally by editing your WebApiConfig.cs and putting the following code:

config.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore

If you're using .NET Core edit the Startup.cs to add

var mvc = services.AddMvc(options =>
        {
           ...
        })
        .AddJsonOptions(x => x.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore);

It is possible yet to use annotations to solve this by putting [JsonIgnore] on the Details property.