Working with nested json file visual basic

Question

i have a nested json file that i want to deserialize, i keep getting an error " Object reference not set to an instance of an object."

here is my json file

[
{
    "Name": "Junius",
    "LastName": "Lekgwara",
    "CellNo": [
        {
            "CellC": "072685345",
            "Voda": "0728589303"
        }
    ]
},
{
    "Name": "Phuti",
    "LastName": "Gravel",
    "CellNo": [
        {
            "CellC": "08377777777",
            "Voda": "089888888888"
        }
    ]
},
{
    "Name": "Donald",
    "LastName": "Gravel",
    "CellNo": [
        {
            "CellC": "0791408989",
            "Voda": "0117689009"
        }
    ]
  }
]

here is my Person class

Public Class Person
Private _Name As String
Public Property Name() As String
    Get
        Return _Name
    End Get
    Set(ByVal value As String)
        _Name = value
    End Set
End Property
Private _LastName As String
Public Property LastName() As String
    Get
        Return _LastName
    End Get
    Set(ByVal value As String)
        _LastName = value
    End Set
End Property
Public Property cellno As CellNo
End Class

Public Class CellNo
Public Property CellC As String
Public Property Voda As String

End Class

PersonList class

Public Class PersonList
Private _ListPerson As List(Of Person)
Public Property ListPerson() As List(Of Person)
    Get
        Return _ListPerson
    End Get
    Set(ByVal value As List(Of Person))
        _ListPerson = value
    End Set
End Property
Sub New()
    _ListPerson = New List(Of Person)
End Sub
End Class

reading json file, when this sub is called i get an error

 Public Async Sub LoadFromFile()
    Dim reader As String = Await GetFile()
    Dim serializer As DataContractJsonSerializer = New DataContractJsonSerializer(GetType(ObservableCollection(Of Person)))
    Dim ms As MemoryStream = New MemoryStream(Encoding.UTF8.GetBytes(reader))
    Dim listOf As ObservableCollection(Of Person) = New ObservableCollection(Of Person)
    listOf = serializer.ReadObject(ms)
    For Each item In listOf
        list.ListPerson.Add(item)
        Debug.WriteLine(item.Name + " " + item.LastName + " " + item.cellno.CellC + " " + item.cellno.Voda) 'Object reference not set to an instance of an object, on item.cellno.CellC and item.cellno.Voda
    Next
End Sub

i want to be able to reference it like

Dim person As Person = New Person()
lblName.Text = person.Name
lblLastName.Text = person.LastName
lblCellCNo.Text= person.cellno.CellC
lblCellVodaNo.Text= person.cellno.Voda

how can i fix this?

Answer 1

Solved the problem by using CellNo as an array

 `"CellNo":[
             "072685345",
             "0728589303"
           ]

   For Each item In listOf
        list.ListPerson.Add(item)
        Debug.WriteLine(item.Name + " " + item.LastName)
        For Each i In item.CellNo
            Debug.WriteLine(i)
        Next
    Next

display

Junius Lekgwara
Cell No: 072685345
Cell No: 0728589303

Phuti Gravel
Cell No: 08377777777
Cell No: 089888888888

Donald Gravel
Cell No: 0791408989
Cell No: 0117689009