Use ProvideProperty as object

Question

I would like to use a class that ProvideProperty as object inside the disigner but it seems I can't use it when the property is an Object. A string works well.

I can set and get within the code but not in the designer.

Big thx

My code :

Imports System.Windows.Forms
Imports System.ComponentModel

<ProvideProperty("Champ", GetType(Control))> _
<ProvideProperty("Valeur", GetType(Control))> _
<ProvideProperty("Comparaison", GetType(Control))> _
Public Class ProprietesEtendues
    Implements IExtenderProvider

    Public Enum CompareType
        Egal
        Different
        PlusGrand
        PlusGrandEgal
        PlusPetit
        PlusPetitEgal
    End Enum

    Private _champ As New Dictionary(Of IntPtr, String)
    Private _val As New Dictionary(Of IntPtr, Object)
    Private _comp As New Dictionary(Of IntPtr, CompareType)

    'Propriété Comparaison
    Public Function GetChamp(ByVal c As Control) As String
        Dim strRetour As String = ""
        _champ.TryGetValue(c.Handle, strRetour)
        Return strRetour
    End Function

    <DefaultValue(""), Category("Data"), Description("Ajoute une propriété de type String")> _
    Public Sub SetChamp(ByVal c As Control, ByVal value As String)
        _champ(c.Handle) = value
    End Sub

    'Propriété Valeur
    Public Function GetValeur(ByVal c As Control) As Object
        Dim objRetour As Object = ""
        _val.TryGetValue(c.Handle, objRetour)
        Return objRetour
    End Function

    <DefaultValue(""), Category("Data"), Description("Ajoute une propriété de type Object")> _
    Public Sub SetValeur(ByVal c As Control, ByVal value As Object)
        _val(c.Handle) = value
    End Sub

    'Propriété Comparaison
    Public Function GetComparaison(ByVal c As Control) As CompareType
        Dim ctRetour As CompareType = CompareType.Egal
        _comp.TryGetValue(c.Handle, ctRetour)
        Return ctRetour
    End Function

    <DefaultValue(CompareType.Egal), Category("Data"), Description("Ajoute une propriété de type CompareType")> _
    Public Sub SetComparaison(ByVal c As Control, ByVal value As CompareType)
        _comp(c.Handle) = value
    End Sub

    Public Function CanExtend(ByVal target As [Object]) As Boolean Implements IExtenderProvider.CanExtend
        Return True
    End Function
End Class

Answer 1

Normaly, you can put at least a string like the Tag property

If a string is good enough then you can apply the [TypeConverter] attribute:

<TypeConverter(GetType(StringConverter))> _
Public Function GetValeur(ByVal c As Control) As Object
    Dim objRetour As Object = ""
    _val.TryGetValue(c.Handle, objRetour)
    Return objRetour
End Function

<DefaultValue(""), Category("Data"), Description("Ajoute une propriété de type Object")> _
<TypeConverter(GetType(StringConverter))> _
Public Sub SetValeur(ByVal c As Control, ByVal value As Object)
    _val(c.Handle) = value
End Sub