Get json value in VB.NET - json

Question

How can I get the name of a key in a json file? I have a json that I'm parsing in VB.NET and one of the 'fields' have a dynamic name (it changes). What could I do to get the key name?
For example:
...
"one":{
"two":{
"example":[
{
"aaa":"test",
"bbb":"test",
"ccc":"test"
},
...
I'm getting correctly all the values (test, test, test...) and the keys 'one', 'two', have always the same name. But the key 'example' changes the name according the json file information. How could I identify the key text?

Answer 1

I wrote a piece of code that converts JSON into a XDocument here: https://github.com/dday9/.NET-JSON-Transformer
If you were to use that code, then you could get the node that represents your "two" object and then get the first child node in to. By doing this, you're essentially getting the array by an Index instead of by a name.
Here is a quick example of what I mean:
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
Fiddle: Live Demo

Answer 2

This piece will allow to get data from an unknown JSON structure, without having to define a class.
Sample
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)
The Function, very self descriptive:
''' <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
End Function

Answer 3

I see this is solved but would like to suggest another solution for future readers. The JavaScriptSerializer can return a nested dictionary collection (Of String, Object). I find it easier to explore the result in debug while coding. The code below shows an example of how to navigate the collections.
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)