MVC 4，结果实体循环引用 [英] MVC 4, Upshot entities cyclic references

问题描述

我有一个DbDataController它提供设备的清单。

 公开的IQueryable＆LT; BettrFit.Models.Equipment＆GT; GetEquipment（）{
        变种Q = DbContext.EquipmentSet.OrderBy（E =＆GT; e.Name）;
        返回q;
    }
 

在我搭建的观点一切看起来正常。

但设备包含EquipmentType的HashSet的成员。我想在我看来，以显示这种类型的，也可以（通过多选列表）将数据添加到设备的EquipmentType集合。

但是，如果我尝试包括EquipmentType在我的LINQ查询的它的序列化过程中失败

 公开的IQueryable＆LT; BettrFit.Models.Equipment＆GT; GetEquipment（）{
        变种Q = DbContext.EquipmentSet.Include（EquipmentType）排序依据（E =＆GT; e.Name）。
        返回q;
    }
 

对象图的类型EquipmentType包含周期和不能被序列化，如果参考禁止追踪

如何切换在引用回溯？

也许问题在于EquipmentType是通过HashSet的背面联？但我不我的查询.INCLUDE（EquipmentType.Equipment）。所以这应该没问题。

如何结果生成模式？我只找到EquipmentViewModel.js文件，但这个不包含任何模型成员。

下面是我的模型类：

 公共类设备
{
    公共设备（）
    {
        this.Exercise =新的HashSet＆LT;运动与GT;（）;
        this.EquipmentType =新的HashSet＆LT; EquipmentType＆GT;（）;
        this.UserDetails =新的HashSet＆LT;＆的UserDetails GT;（）;
    }    公众诠释ID {搞定;组; }
    公共字符串名称{;组; }
    公共字符串描述{搞定;组; }
    公共字符串图片{搞定;组; }
    公共字符串链接{搞定;组; }
    公共字符串生产者{搞定;组; }
    公共字符串视频{搞定;组; }    公共虚拟的ICollection＆LT; EquipmentType＆GT; EquipmentType {搞定;组; }
    公共虚拟的ICollection＆LT;＆的UserDetails GT; {的UserDetails获得;组; }
}
公共类EquipmentType
{
    公共EquipmentType（）
    {
        this.Equipment =新的HashSet＆LT;设备及GT;（）;
        this.UserDetails =新的HashSet＆LT;＆的UserDetails GT;（）;
    }    公众诠释ID {搞定;组; }
    公共字符串名称{;组; }
    公共字符串描述{搞定;组; }    公共虚拟的ICollection＆LT;设备＆GT;设备{搞定;组; }
    公共虚拟的ICollection＆LT;＆的UserDetails GT; {的UserDetails获得;组; }
}
 

解决方案

我想通了 - 部分如何解决循环引用问题

我只是迭代查询我的收藏（与包括（）），并设置反向引用父为NULL。这工作了，否则就破坏了服务器上的序列化问题。

唯一的问题是现在数据实体的更新 - 它的失败，因为引用entitycollection的数组都是静态的...

I have a DbDataController which delivers a List of Equipment.

    public IQueryable<BettrFit.Models.Equipment> GetEquipment() {
        var q= DbContext.EquipmentSet.OrderBy(e => e.Name);
        return q;
    }

In my scaffolded view everything looks ok.

But the Equipment contains a HashSet member of EquipmentType. I want to show this type in my view and also be able to add data to the EquipmentType collection of Equipment (via a multiselect list).

But if I try to include the "EquipmentType" in my linq query it fails during serialisation.

    public IQueryable<BettrFit.Models.Equipment> GetEquipment() {
        var q= DbContext.EquipmentSet.Include("EquipmentType").OrderBy(e => e.Name);
        return q;
    }

"Object Graph for Type EquipmentType Contains Cycles and Cannot be Serialized if Reference Tracking is Disabled"

How can I switch on the "backtracking of references"?

Maybe the problem is that the EquipmentType is back-linking through a HashSet? But I do not .include("EquipmentType.Equipment") in my query. So that should be ok.

How is Upshot generating the model? I only find the EquipmentViewModel.js file but this does not contain any model members.

Here are my model classes:

public class Equipment
{
    public Equipment()
    {
        this.Exercise = new HashSet<Exercise>();
        this.EquipmentType = new HashSet<EquipmentType>();
        this.UserDetails = new HashSet<UserDetails>();
    }

    public int ID { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public string Picture { get; set; }
    public string Link { get; set; }
    public string Producer { get; set; }
    public string Video { get; set; }

    public virtual ICollection<EquipmentType> EquipmentType { get; set; }
    public virtual ICollection<UserDetails> UserDetails { get; set; }
}
public class EquipmentType
{
    public EquipmentType()
    {
        this.Equipment = new HashSet<Equipment>();
        this.UserDetails = new HashSet<UserDetails>();
    }

    public int ID { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }

    public virtual ICollection<Equipment> Equipment { get; set; }
    public virtual ICollection<UserDetails> UserDetails { get; set; }
}

解决方案

I figured out - partially how to solve the circular reference problem.

I just iterated over my queried collection (with Include() ) and set the backreferences to the parent to NULL. That worked for the serialisation issue which otherwise already breaks on the server.

The only problem now is the update of a data entity - its failing because the arrays of the referenced entitycollection are static...

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