[Débutant] MVVM ListBox ItemSource Binding

Bonjour !

Je me trouve devant un problème de rafraichissement de ma listbox alors que j'ai une ObservableCollection en ItemSource ; j'utilise le pattern MVVM.

mon ViewModel :

Code:

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Public Class MainWindowViewModel
    'implémente INotifyPropertyChanged & IDisposable
    Inherits ViewModelBase
 
    'Ma collection bindée
    Private _personList As ObservableCollection(Of Person)
    Public Property PersonList() As ObservableCollection(Of Person)
        Get
            If IsNothing(_personList) Then
                _personList = GetPersonList()
            End If
            Return _personList
        End Get
        Set(ByVal value As ObservableCollection(Of Person))
            _personList = value
            OnPropertyChanged(Me, "PersonList")
        End Set
    End Property
 
    'constructeurs (vides)
    Sub New()
    End Sub
    Sub New(ByVal mainWindow As MainWindow)
    End Sub
 
    'génère une premier dataset
    Private Function GetPersonList() As ObservableCollection(Of Person)
        Dim l As New ObservableCollection(Of Person)
        l.Add(New Person("a", "b", "1", 1))
        l.Add(New Person("c", "d", "2", 2))
        l.Add(New Person("e", "f", "3", 3))
        l.Add(New Person("g", "h", "4", 4))
        l.Add(New Person("i", "j", "5", 5))
        Return l
    End Function
    'génère une deuxième dataset
    Private Function GetPersonList2() As ObservableCollection(Of Person)
        Dim l As New ObservableCollection(Of Person)
        l.Add(New Person("g", "h", "4", 4))
        l.Add(New Person("e", "f", "3", 3))
        l.Add(New Person("i", "j", "5", 5))
        l.Add(New Person("c", "d", "2", 2))
        l.Add(New Person("a", "b", "1", 1))
        Return l
    End Function
    'charge le deuxième dataset
    Public Sub Load()
        Me.PersonList = GetPersonList2()
    End Sub
    'supprime le premier élément de la liste
    Public Sub Delete()
        If Me.PersonList.Count > 0 Then
            Me.PersonList.RemoveAt(0)
            OnPropertyChanged(Me, "PersonList")
        End If
 
    End Sub
End Class

et voici mon xaml :

Code:

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<Window.Resources>
        <local:MainWindowViewModel x:Key="MainWindowViewModelDataSource"/>
	</Window.Resources>
 
    <Grid Name="stpnl" >
        <Grid.Resources>
            <DataTemplate x:Key="PersonTemplate" >
                <StackPanel Orientation="Horizontal">
                    <TextBlock Text="{Binding Path=Name}" MinWidth="50" Margin="5"/>
                    <TextBlock Text="{Binding Path=SubName}" MinWidth="50" Margin="5"/>
                    <TextBlock Text="{Binding Path=Age}" MinWidth="50" Margin="5"/>
                    <TextBlock Text="{Binding Path=ID}" MinWidth="50" Margin="5"/>
                </StackPanel>
            </DataTemplate>
        </Grid.Resources>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="30"/>
        </Grid.RowDefinitions>
        <ListBox Name="lbox"  Margin="5" Grid.Row="0"
         DataContext="{Binding Source={StaticResource MainWindowViewModelDataSource}}"		 
		 ItemsSource="{Binding PersonList, Mode=TwoWay}"
         ItemTemplate="{StaticResource PersonTemplate}">            
        </ListBox>
 
        <StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Center">
            <Button Content="Load" Name="Button1" Width="150" Margin="20,0,20,0"/>
            <Button Content="Delete" Name="Button2" Width="150" Margin="20,0,20,0" />
        </StackPanel>

L'appel du Load et Delete sont faits dans xaml.vb

Code:

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    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click
        Dim d As MainWindowViewModel = Me.DataContext
        d.Load()
    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button2.Click
        Dim d As MainWindowViewModel = Me.DataContext
        d.Delete()
    End Sub

Je ne comprend absolument pas ce qui cloche : la listbox est correctement remplie au démarrage, je passe bien dans les OnPropertyChanged, mais aucune modification de la View

Si quelqu'un a une idée ??

Merci !!

Stéphane.