Set default value when deserializing JSON missing properties

I'm trying to assign a Default value to my class, when I don't have the property listed in the JSON.

This is the class I'm using to deserialize JSON

Public Class cls_horarios

   
    Public Class Expediente

        Public Property expediente_opcao_domingo As ExpedienteOpcaoDomingo
        Public Property expediente_opcao_segunda As ExpedienteOpcaoSegunda
        Public Property expediente_opcao_terca As ExpedienteOpcaoTerca
        Public Property expediente_opcao_quarta As ExpedienteOpcaoQuarta
        Public Property expediente_opcao_quinta As ExpedienteOpcaoQuinta
        Public Property expediente_opcao_sexta As ExpedienteOpcaoSexta
        Public Property expediente_opcao_sabado As ExpedienteOpcaoSabado
        Public Property expediente_feriados As String
        Public Property expediente_bloqueio_pc As String
        Public Property expediente_bloqueio_tolerancia As String
    End Class

    Public Class ExpedienteOpcaoDomingo
        Public Property isDiaUtil As Integer
        Public Property hora_inicial As String
        Public Property hora_final As String
    End Class

    Public Class ExpedienteOpcaoQuarta
     Public Property isDiaUtil As Integer
        Public Property hora_inicial As String
        Public Property hora_final As String
    End Class

    Public Class ExpedienteOpcaoQuinta
        Public Property isDiaUtil As Integer
        Public Property hora_inicial As String
        Public Property hora_final As String
    End Class

    Public Class ExpedienteOpcaoSegunda
        Public Property isDiaUtil As Integer
        Public Property hora_inicial As String
        Public Property hora_final As String
    End Class

    Public Class ExpedienteOpcaoSexta
        Public Property isDiaUtil As Integer
        Public Property hora_inicial As String
        Public Property hora_final As String
    End Class

    Public Class ExpedienteOpcaoTerca
        Public Property isDiaUtil As Integer
        Public Property hora_inicial As String
        Public Property hora_final As String
    End Class
   
    Public Class Result
        Public Property expediente As List(Of Expediente)
    End Class

    Public Class Root
        Public Property result As Result
    End Class

This is the JSON I am trying to deserialize:

{
  "result": {
    "expediente": [{
      "expediente_opcao_domingo": {
        "isDiaUtil": 0,
        "hora_inicial": null,
        "hora_final": null
      },
      "expediente_opcao_segunda": {
        "isDiaUtil": 1,
        "hora_inicial": "09:00",
        "hora_final": "18:48"
      },
      "expediente_opcao_terca": {
        "isDiaUtil": 1,
        "hora_inicial": "09:00",
        "hora_final": "18:48"
      },
      "expediente_opcao_quarta":
      {
        "isDiaUtil": 1,
        "hora_inicial": "09:00",
        "hora_final": "18:48"
      },
      "expediente_opcao_sexta": {
        "isDiaUtil": 1,
        "hora_inicial": "09:00",
        "hora_final": "18:48"
      },
      "expediente_opcao_sabado": {
        "isDiaUtil": 0,
        "hora_inicial": null,
        "hora_final": null
      },
      "expediente_nome": "padr\u00e3o",
      "expediente_feriados": "0",
      "expediente_bloqueio_pc": 0,
      "expediente_bloqueio_tolerancia": "0"
    }],
     }
}

In this scenario, what I'm trying to do is assign a default value so that it doesn't have the properties in the JSON, the default value is set, so that it can be tested, just remove the line that is identified in the JSON

and this is the code I'm using to read the JSON

Public Sub PreencheConfiguracoesColaborador(ByVal dados As String)

        '//INICIO EXPEDIENTE DO COLABORADOR


        Dim horarioColab As cls_horarios.Root = JsonConvert.DeserializeObject(Of cls_horarios.Root)(dados)
        expediente_colab_quantidade = 0

        
        Try
            For Each item As Expediente In horarioColab.result.expediente

                expediente_colab_feriado = item.expediente_feriados
                expediente_colab_bloqueio_pc = item.expediente_bloqueio_pc
                expediente_colab_bloqueio_tolerancia = item.expediente_bloqueio_tolerancia

                expediente_colab_domingo = item.expediente_opcao_domingo.isDiaUtil
                expediente_colab_domingo_hora_entrada = FormatDateTime(item.expediente_opcao_domingo.hora_inicial.ToString, DateFormat.LongTime)
                expediente_colab_domingo_hora_saida = FormatDateTime(item.expediente_opcao_domingo.hora_final.ToString, DateFormat.LongTime)

                expediente_colab_segunda = item.expediente_opcao_segunda.isDiaUtil
                expediente_colab_segunda_hora_entrada = FormatDateTime(item.expediente_opcao_segunda.hora_inicial.ToString, DateFormat.LongTime)
                expediente_colab_segunda_hora_saida = FormatDateTime(item.expediente_opcao_segunda.hora_final.ToString, DateFormat.LongTime)

                expediente_colab_terca = item.expediente_opcao_terca.isDiaUtil
                expediente_colab_terca_hora_entrada = FormatDateTime(item.expediente_opcao_terca.hora_inicial.ToString, DateFormat.LongTime)
                expediente_colab_terca_hora_saida = FormatDateTime(item.expediente_opcao_terca.hora_final.ToString, DateFormat.LongTime)


                expediente_colab_quarta = item.expediente_opcao_quarta.isDiaUtil
                expediente_colab_quarta_hora_entrada = FormatDateTime(item.expediente_opcao_quarta.hora_inicial.ToString, DateFormat.LongTime)
                expediente_colab_quarta_hora_saida = FormatDateTime(item.expediente_opcao_quarta.hora_final.ToString, DateFormat.LongTime)

                expediente_colab_quinta = item.expediente_opcao_quinta.isDiaUtil
                expediente_colab_quinta_hora_entrada = FormatDateTime(item.expediente_opcao_quinta.hora_inicial.ToString, DateFormat.LongTime)
                expediente_colab_quinta_hora_saida = FormatDateTime(item.expediente_opcao_quinta.hora_final.ToString, DateFormat.LongTime)

                expediente_colab_sexta = item.expediente_opcao_sexta.isDiaUtil
                expediente_colab_sexta_hora_entrada = FormatDateTime(item.expediente_opcao_sexta.hora_inicial.ToString, DateFormat.LongTime)
                expediente_colab_sexta_hora_saida = FormatDateTime(item.expediente_opcao_sexta.hora_final.ToString, DateFormat.LongTime)

                expediente_colab_sabado = item.expediente_opcao_sabado.isDiaUtil
                expediente_colab_sabado_hora_entrada = FormatDateTime(item.expediente_opcao_sabado.hora_inicial.ToString, DateFormat.LongTime)
                expediente_colab_sabado_hora_saida = FormatDateTime(item.expediente_opcao_sabado.hora_final.ToString, DateFormat.LongTime)


                'expediente_colab_expediente_nome = item.expediente_nome
                expediente_colab_quantidade += 1
                Console.WriteLine("Feriado: " & expediente_colab_feriado & " Bloqueio Pc: " & expediente_colab_bloqueio_pc & " Bloqueio Tolerancia: " & expediente_colab_bloqueio_tolerancia & " Expediente Nome: " & expediente_colab_expediente_nome)

            Next

        Catch ex As Exception
            writeExeption(ex, False)
            Console.WriteLine("Erro Expediente: " & ex.Message)
        End Try

    End Sub

I have already tried the following proposed solutions right here on SO:

https://stackoverflow.com/questions/29611445/default-value-for-missing-properties-with-json-net

https://stackoverflow.com/questions/15452450/why-when-i-deserialize-with-json-net-ignores-my-default-value

But all without success.

What I need is to set the default value when the JSON properties are missing, so I ask for everyone's help to resolve this issue.

You have a few problems here:

1. There is no value for the property "expediente_opcao_quinta" in the JSON, thus Expediente.expediente_opcao_quinta is null.

2. There are several string whose values in the JSON is explicitly null, e.g. "result[0].expediente.expediente_opcao_sabado".

3. There are also missing string-valued properties whose values default to null.

The easiest way to resolve these problems is to automatically initialize your properties to non-null values when constructed as shown in Initializing an Auto-Implemented Property, and apply <JsonProperty(NullValueHandling := NullValueHandling.Ignore)> to any property that should never be null to force Json.NET to ignore null values when deserializing and serializing.

Thus your data model should look like:

Public Class Expediente
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property expediente_opcao_domingo As ExpedienteOpcao = New ExpedienteOpcao()
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property expediente_opcao_segunda As ExpedienteOpcao = New ExpedienteOpcao()
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property expediente_opcao_terca As ExpedienteOpcao = New ExpedienteOpcao()
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property expediente_opcao_quarta As ExpedienteOpcao = New ExpedienteOpcao()
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property expediente_opcao_quinta As ExpedienteOpcao = New ExpedienteOpcao()
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property expediente_opcao_sexta As ExpedienteOpcao = New ExpedienteOpcao()
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property expediente_opcao_sabado As ExpedienteOpcao = New ExpedienteOpcao()
Public Property expediente_feriados As String
Public Property expediente_bloqueio_pc As String
Public Property expediente_bloqueio_tolerancia As String
End Class
Public Class ExpedienteOpcao
Public Property isDiaUtil As Integer
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property hora_inicial As String = ""
<JsonProperty(NullValueHandling := NullValueHandling.Ignore)> _
Public Property hora_final As String = ""
End Class
Public Class Result
Public Property expediente As List(Of Expediente)
End Class
Public Class Root
Public Property result As Result
End Class

Notes:

• You have a seven of identical classes with names like ExpedienteOpcaoDomingo and ExpedienteOpcaoQuarta that seem to correspond to days of the week. I am guessing you created these classes with some code generation tool. Code generation tools will sometimes fail to detect and combine identical types, but since in this case it seems they should be identical, I made them such in my answer.

• In your question you catch and ignore all exceptions. This is generally a bad idea as you lose all information about the cause of the problem, and your code may proceed forward using corrupt data. See e.g. Is catching general exceptions really a bad thing? for some additional discussion.

• While you could use the answers from https://stackoverflow.com/q/29611445/3744182 to use DefaultValueAttribute to provide default values for missing properties with primitive values, you cannot use DefaultValueAttribute to provide a default value for a complex property value such as ExpedienteOpcao due to limitations on attribute parameter types built into the CLR.

Demo fiddle here.