Question

如何在json文件中获取密钥的名称？我有一个json，我在VB.NET中解析，其中一个＆＃39;字段＆＃39;有一个动态名称（它改变）。我该怎么做才能获得密钥名称？

例如：

...

"one":{  
                        "two":{  
                           "example":[  
                              {  
                                 "aaa":"test",
                                 "bbb":"test",
                                 "ccc":"test"
                              },

...

我正确地获取了所有值（测试，测试，测试......），而且其中一个＆＃39;，＆＃39;两个＆＃39;总是具有相同的名称。但关键的例子＆＃39;根据json文件信息更改名称。我怎样才能识别关键文本？

Answer 1

我写了一段代码，将JSON转换为XDocument：https://github.com/dday9/.NET-JSON-Transformer

如果您要使用该代码，那么您可以获得代表您的“两个”对象的节点，然后获取第一个子节点。通过这样做，您实际上是通过索引而不是名称来获取数组。

以下是我的意思的快速示例：

Dim literal As String = "{""two"":{""example"":[{""aaa"":""test"",""bbb"":""test"",""ccc"":""test""}]}}"
Dim xJSON As XDocument = JSON.Parse(literal)
Dim object_two As XElement = xJSON.Descendants("two").FirstOrDefault()
If object_two IsNot Nothing Then
    Dim first_descendent As XElement = object_two.Descendants().Skip(1).FirstOrDefault()

    If first_descendent IsNot Nothing Then
        Console.WriteLine(first_descendent)
    End If
End If

小提琴：Live Demo

Answer 2

我看到这已经解决了，但我想为未来的读者提出另一种解决方案。 JavaScriptSerializer可以返回嵌套的字典集合（Of String，Object）。我发现在编码时更容易在调试中探索结果。下面的代码显示了如何导航集合的示例。

  Dim deserializer As New System.Web.Script.Serialization.JavaScriptSerializer

  Dim text As String = "{""two"":{""example"":[{""aaa"":""test"",""bbb"":""test"",""ccc"":""test""}]}}"
  Dim dict As Dictionary(Of String, Object) = deserializer.DeserializeObject(text)

  Dim keys As Dictionary(Of String, Object).KeyCollection
  keys = dict("two")("example")(0).Keys

  Dim aaaName As String = keys(0)
  Dim aaaValue As String = dict("two")("example")(0)(aaaName)

Answer 3

这部分将允许从未知的 JSON 结构中获取数据，而无需定义类。

样品

Dim serializer As System.Web.Script.Serialization.JavaScriptSerializer
serializer = New JavaScriptSerializer()
' {"elements":[{"handle~":{"emailAddress":"myself@example.com"},"handle":"urn:li:emailAddress:348955221"}]}
dim json as string
Dim obj As System.Collections.Generic.IDictionary(Of String, Object)
obj = serializer.Deserialize(Of System.Collections.Generic.IDictionary(Of String, Object))(json)
dim email as string=string.empty
email = If(GetJsonValue(obj, {"elements", "handle~", "emailAddress"}.ToList()), email)

功能，非常自我描述：

''' <summary>decode json data </summary>
Public Function GetJsonValue(ByVal obj As Object,
                          ByVal key As List(Of String)) As String
   GetJsonValue = Nothing
    '   If the object is an array, assume any element can contain the key
    If obj.GetType Is GetType(Object()) Then 
        For Each newObj As Object In CType(obj, Object())
            Dim tmp As String = GetJsonValue(newObj, key)
            If Not String.IsNullOrEmpty(tmp) Then Return tmp
        Next
    Else
        Dim objEle As System.Collections.Generic.IDictionary(Of String, Object)
        Dim keyName As String
        Dim objKey As String
        '
        keyName = key(0)
        objEle = CType(obj, System.Collections.Generic.IDictionary(Of String, Object))
        objKey = objEle.Keys.ToArray()(0)

        If objEle.ContainsKey(keyName) Then
            Dim temp As Object = objEle.Item(keyName)
            If key.Count > 1 Then
                ' if the element is array, we need to get the array element and move to the next
                key.RemoveAt(0)
                Return GetJsonValue(temp, key)
            Else
                Return temp.ToString()
            End If
        End If
    End If

结束函数

在VB.NET中获取json值

3 个答案: