使用LINQ查询JSON

Question

我收到了一个来自API调用的Json响应。它有几个嵌套层次，如下所示（这是一段片段）:

"Items": [
  {
    "Result": {
      "Id": "191e24b8-887d-e111-96ec-000c29128cee",
      "Name": "Name",
      "StartDate": "2012-04-03T00:00:00+01:00",
      "EndDate": null,
      "Status": {
        "Name": "Active",
        "Value": 5
      },
      "Client": {
        "Id": "35ea10da-b8d5-4ef8-bf23-c829ae90fe60",
        "Name": "client Name",
        "AdditionalItems": {}
      },
      "ServiceAgreement": {
        "Id": "65216699-a409-44b0-8294-0e995eb05d9d",
        "Name": "Name",
        "AdditionalItems": {
          "ScheduleBased": true,
          "PayFrequency": {
            "Id": "981acb72-8291-de11-98fa-005056c00008",
            "Name": "Weekly",
            "AdditionalItems": {}
          },
          "PayCycle": [
            {
              "Name": "Schedule Based",
              "ScheduleBased": true,
              "SelfBilling": false,
              "Id": "a8a2ecc4-ff79-46da-a135-743b57808ec3",
              "CreatedOn": "2011-09-16T23:32:19+01:00",
              "CreatedBy": "System Administrator",
              "ModifiedOn": "2011-09-16T23:32:19+01:00",
              "ModifiedBy": "System Administrator",
              "Archived": false
            }
          ]
        }
      },
}
]
...

我想做的是使用 Linq 从 PayCycle 节点检索数据。例如，我可以使用控制器中以下的 Linq 获取值为 true 的项目：Result.ServiceAgreement.AdditionalItems.SchedultedBased：

var result = from p in data["Data"]["Items"].Children()
             where (bool)p["Result"]["ServiceAgreement"]["AdditionalItems"]["ScheduleBased"] == true
             select new
             {
                 Name = (string)p["Result"]["Client"]["Name"],
                 Id = (string)p["Result"]["Client"]["Id"]
             };

现在我需要获取Result.ServiceAgreement.AdditionalItems.Paycycle.ScheduleBased和SelfBilling属性。如果PayCycle也是一个数组，那么如何像在上面的Linq中对Data.Items所做的那样获取子项，以便我可以在这两个项目上进行where子句过滤呢？

- KDee

Answer 1

您可以将JSON反序列化为dynamic对象，然后使用Linq to Objects：

    [TestMethod]
    public void TestMethod1()
    {
        const string json = @"""Items"": [
{
""Result"": {
  ""Id"": ""191e24b8-887d-e111-96ec-000c29128cee"",
  ""Name"": ""Name"",
  ""StartDate"": ""2012-04-03T00:00:00+01:00"",
  ""EndDate"": null,
  ""Status"": {
    ""Name"": ""Active"",
    ""Value"": 5
  },
  ""Client"": {
    ""Id"": ""35ea10da-b8d5-4ef8-bf23-c829ae90fe60"",
    ""Name"": ""client Name"",
    ""AdditionalItems"": {}
  },
  ""ServiceAgreement"": {
    ""Id"": ""65216699-a409-44b0-8294-0e995eb05d9d"",
    ""Name"": ""Name"",
    ""AdditionalItems"": {
      ""ScheduleBased"": true,
      ""PayFrequency"": {
        ""Id"": ""981acb72-8291-de11-98fa-005056c00008"",
        ""Name"": ""Weekly"",
        ""AdditionalItems"": {}
      },
      ""PayCycle"": [
        {
          ""Name"": ""Schedule Based"",
          ""ScheduleBased"": true,
          ""SelfBilling"": false,
          ""Id"": ""a8a2ecc4-ff79-46da-a135-743b57808ec3"",
          ""CreatedOn"": ""2011-09-16T23:32:19+01:00"",
          ""CreatedBy"": ""System Administrator"",
          ""ModifiedOn"": ""2011-09-16T23:32:19+01:00"",
          ""ModifiedBy"": ""System Administrator"",
          ""Archived"": false
        }
      ]
    }
  }
}
}
]";
        dynamic data = System.Web.Helpers.Json.Decode("{" + json + "}");

        var result = from i in (IEnumerable<dynamic>)data.Items
                     where i.Result.ServiceAgreement.AdditionalItems.ScheduleBased == true
                     select new
                            {
                                i.Result.Client.Name,
                                i.Result.Client.Id
                            };

        Assert.AreEqual(1, result.Count());
        Assert.AreEqual("client Name", result.First().Name);
        Assert.AreEqual("35ea10da-b8d5-4ef8-bf23-c829ae90fe60", result.First().Id);
    }

请注意，我不得不在您的示例JSON字符串周围添加大括号{和}，否则.NET JSON解析器将无法识别它。

- CodingWithSpike

---

我稍微修改了一下我的代码，因为PayCycle集合将只返回集合中的一个项目。所以，为了获取例如SelfBilling属性，我在where子句中做了以下操作：where (bool)p["Result"]["ServiceAgreement"]["AdditionalItems"]["PayCycle"][0]["SelfBilling"] == false。这给了我我想要的结果。 - KDee

Answer 2

首先，我不熟悉使用这种格式["some"]["thing"]编写LINQ/LAMBDA。 我的第一步将是创建一些类/对象来存储数据，以便在之后轻松创建任何代码。

例如：

public class Result
{
    public Guid Id { get; set; } 
    public string Name { get; set; },
    public DateTime StartDate  { get; set; }
    //you get the idea
}

但是也许可以尝试以下方法？

    var result = from p in data["Data"]["Items"].Children()
                 where (bool)p["Result"]["ServiceAgreement"]["AdditionalItems"]["ScheduleBased"] == true
                    && (p["Result"]["ServiceAgreement"]["AdditionalItems"]["PayCycle"]).Where(o => o.["ScheduleBased"] == true)
                 select new
                 {
                     Name = (string)p["Result"]["Client"]["Name"],
                     Id = (string)p["Result"]["Client"]["Id"]
                 };

- Rohan Büchner