Question

我使用投影（显式加载）来调用和过滤从子表返回的集合数据，并通过RESTful Api服务公开结果。 json很好，但它重复了子表集合对象。使用“AsNoTracking（）”方法会使json输出中的嵌套子集合无效。

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。
另见上面的链接在MSDN

Answer 2

我能够通过使用第三方IncludeFilter（）扩展方法的急切加载来解决此问题。 https://github.com/zzzprojects/EntityFramework-Plus/issues

RESTful API实体框架上下文重复子集合数据C＃

2 个答案: