Question

I have a custom control that has a property that is an ObservableCollection of another custom control. I can’t seem to get the DependencyProperty change event to fire in design time. I have tried to use CoerceValueCallback this doesn’t fire either. can anyone give me some direction. Every thing else is working just fine in runtime i just can’t get this to fire so i can update the control in designtime. Many thanks in advance.

Public Shared ReadOnly ArcsProperty As DependencyProperty = DependencyProperty.Register("Arcs", GetType(ObservableCollection(Of OPCWPF.OPCWPFArcControl)), GetType(OPCWPFPie), New PropertyMetadata(New ObservableCollection(Of OPCWPF.OPCWPFArcControl), New PropertyChangedCallback(AddressOf ArcsPropertyChanged), New CoerceValueCallback(AddressOf CoerceArcs)))

 ' Arc Quantity
<Description("Collection of Arcs"), _
Category("Common Properties")> _
Public Property Arcs() As ObservableCollection(Of OPCWPF.OPCWPFArcControl)
    Get
        Return DirectCast(Me.GetValue(ArcsProperty), ObservableCollection(Of OPCWPF.OPCWPFArcControl))
    End Get

    Set(ByVal value As ObservableCollection(Of OPCWPF.OPCWPFArcControl))
        Me.SetValue(ArcsProperty, value)
    End Set
End Property

Answer 1

The simple solution (maybe not the best) but it got me what i was looking for.

 Public Overrides Sub OnApplyTemplate()
    MyBase.OnApplyTemplate()
    AddHandler Arcs.CollectionChanged, AddressOf UpdateControl
 End Sub