如何在vb.net上反序列化这个json？

Question

我有json格式的数据：

{
   "status":{
      "timestamp":"2021-01-07T17:13:48.471Z",
      "error_code":0,
      "error_message":null,
      "elapsed":12,
      "credit_count":1,
      "notice":null,
      "total_count":4115
   },
   "data":[
      {
         "id":1,
         "name":"Bitcoin",
         "symbol":"BTC",
         "slug":"bitcoin",
         "num_market_pairs":9732,
         "date_added":"2013-04-28T00:00:00.000Z",
         "tags":[
            "mineable",
            "pow",
            "sha-256",
            "store-of-value",
            "state-channels"
         ],
         "max_supply":21000000,
         "circulating_supply":18593700,
         "total_supply":18593700,
         "platform":null,
         "cmc_rank":1,
         "last_updated":"2021-01-07T17:12:02.000Z",
         "quote":{
            "USD":{
               "price":39362.167971369854,
               "volume_24h":78135138852.86674,
               "percent_change_1h":2.61231359,
               "percent_change_24h":12.47756102,
               "percent_change_7d":36.98956944,
               "market_cap":731888342609.2596,
               "last_updated":"2021-01-07T17:12:02.000Z"
            }
         }
      },
      {
         "id":1027,
         "name":"Ethereum",
         "symbol":"ETH",
         "slug":"ethereum",
         "num_market_pairs":5934,
         "date_added":"2015-08-07T00:00:00.000Z",
         "tags":[
            "mineable",
            "pow",
            "smart-contracts"
         ],
         "max_supply":null,
         "circulating_supply":114155463.749,
         "total_supply":114155463.749,
         "platform":null,
         "cmc_rank":2,
         "last_updated":"2021-01-07T17:12:02.000Z",
         "quote":{
            "USD":{
               "price":1261.606649005652,
               "volume_24h":39345516218.36576,
               "percent_change_1h":3.1558102,
               "percent_change_24h":7.80752209,
               "percent_change_7d":71.81090319,
               "market_cap":144019292086.06207,
               "last_updated":"2021-01-07T17:12:02.000Z"
            }
         }
      }
   ]
}

在vb.net中，通过特殊的粘贴，我得到了这个定义：

Public Class Rootobject
    Public Property status As Status
    Public Property data() As Datum
End Class

Public Class Status
    Public Property timestamp As Date
    Public Property error_code As Integer
    Public Property error_message As Object
    Public Property elapsed As Integer
    Public Property credit_count As Integer
    Public Property notice As Object
    Public Property total_count As Integer
End Class

Public Class Datum
    Public Property id As Integer
    Public Property name As String
    Public Property symbol As String
    Public Property slug As String
    Public Property num_market_pairs As Integer
    Public Property date_added As Date
    Public Property tags() As String
    Public Property max_supply As Integer
    Public Property circulating_supply As Integer
    Public Property total_supply As Integer
    Public Property platform As Object
    Public Property cmc_rank As Integer
    Public Property last_updated As Date
    Public Property quote As Quote
End Class

Public Class Quote
    Public Property USD As USD
End Class

Public Class USD
    Public Property price As Single
    Public Property volume_24h As Single
    Public Property percent_change_1h As Single
    Public Property percent_change_24h As Single
    Public Property percent_change_7d As Single
    Public Property market_cap As Single
    Public Property last_updated As Date
End Class

但是当我尝试使用此命令进行反序列化时

Dim m As IEnumerable(Of Rootobject) = 
    JsonConvert.DeserializeObject(Of IEnumerable(Of Rootobject))(res)

我得到了这个错误：

Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON object 
    (e.g. {"name":"value"}) into type 
    'System.Collections.Generic.IEnumerable`1[CoinMarketCap.Rootobject]' 
    because the type requires a JSON array (e.g. [1,2,3]) 
    to deserialize correctly. To fix this error either change the JSON to a
    JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a 
    normal .NET type (e.g. not a primitive type like integer, not a
    collection type like an array or List) that can be deserialized from a 
    JSON object. JsonObjectAttribute can also be added to the type to force 
    it to deserialize from a JSON object. Path 'status', line 1, position 10.'

我被困住了..。有什么想法吗？提前谢谢。

Answer 1

要修复此错误，可以将JSON更改为JSON数组(例如，1,2,3)，或者通过更改反序列化类型，使其成为可以从JSON对象反序列化的普通.NET类型(例如，不是像integer这样的原始类型，也不是像数组或列表这样的集合类型)。

换句话说，改变

Dim m As IEnumerable(Of Rootobject) = JsonConvert.DeserializeObject(Of IEnumerable(Of Rootobject))(res)

至

Dim m As Rootobject = JsonConvert.DeserializeObject(Of Rootobject)(res)