RESTful API Entity Framework 上下文重复子集合数据 C#

Question

我正在使用投影（显式加载）来调用和过滤从子 table 返回的集合数据，结果通过 RESTful Api 服务公开。 json 很好，但它重复了子 table 集合对象。使用 "AsNoTracking()" 方法会使 json 输出中的嵌套子集合无效，这是不正确的。

下面是我的代码和 json 输出。我需要帮助来阻止子对象重复

public IQueryable<ApiViewModel> getAllActive()
{
        //Explicit loading (projection)
        var result = db.Markets
            .Where(p => p.IsActive == true)
            .Select(p => new ApiViewModel()
            {
                Market = p,
                TravelCentres = p.TravelCentres.Where(x => x.IsActive == true)
            });

    return result;
}

JSON 输出：

[
  {
    "Market": {
        "MarketId": "AE",
        "Name": "Arabian Emirates",
        "TravelCentres": [
            {
                "City": "New Lynn, New Zealand",
                "Address": "now",
                "Telephone": "09169647771",
                "Email": "test@wak.com"
            },
            {
                "City": "Uyo, Nigeria",
                "Address": "Ewet housing",
                "Telephone": null,
                "Email": null
            },
            {
                "City": "Lagos, Nigeria",
                "Address": "no",
                "Telephone": "09993",
                "Email": "patricko@wak.com"
            }
        ]
    },
    "TravelCentres": [
        {
            "City": "New Lynn, New Zealand",
            "Address": "now",
            "Telephone": "09169647771",
            "Email": "test@wak.com"
        },
        {
            "City": "Uyo, Nigeria",
            "Address": "Ewet housing",
            "Telephone": null,
            "Email": null
        },
        {
            "City": "Lagos, Nigeria",
            "Address": "no",
            "Telephone": "09993",
            "Email": "patricko@wak.com"
        }
    ]
  }
]

Answer 1

尝试 Distinct() 方法。
另见上文 link 在MSDN

Answer 2

我能够通过使用预加载和第 3 方 IncludeFilter() 扩展方法来解决问题。 https://github.com/zzzprojects/EntityFramework-Plus/issues

RESTful API Entity Framework 上下文重复子集合数据 C#

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c#

rest

json

entity-framework

restful-architecture