在VB.NET中获取json值

Question

如何在json文件中获得密钥的名称？我在VB.NET中解析一个json，其中一个“字段”有一个动态名称(它会发生变化)。我能做些什么才能弄到钥匙的名字？

例如：

..。

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

..。

我得到了所有的值(测试，测试，测试.)而键‘1’，‘2’，总是有相同的名字。但是键‘示例’根据json文件信息更改名称。我怎样才能识别关键的文本？

Answer 1

我认为这个问题已经解决了，但我想为未来的读者提出另一个解决方案。JavaScriptSerializer可以返回嵌套的字典集合(字符串、对象)。我发现在编写代码时更容易探索调试的结果。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 2

我在这里编写了一段将JSON转换为XDocument的代码：https://github.com/dday9/.NET-JSON-Transformer

如果要使用该代码，则可以获取表示“两个”对象的节点，然后将第一个子节点输入到。通过这样做，您实际上是通过索引而不是名称来获得数组。

下面是我的意思的一个简单例子：

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：现场演示

Answer 3

这部分允许从未知的JSON结构中获取数据，而不必定义类。

示例

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

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