WPF: PropertyChangedCallback triggered only once

Question

I have a user control, which exposes a DependencyProperty called VisibileItems Every time that property gets updated, i need to trigger another event. To achieve that, i ad

Answer 1

I have the same issue in my code and Luke is right. I called SetValue by mystake inside the PropertyChangedCallback causing a potential infinite loop. WPF prevent this disabling silently the callback !!

my WPF UserControl is

PatchRenderer

my C# property is Note:

    [Description("Note displayed with star icons"), 
    Category("Data"),
    Browsable(true), 
    EditorBrowsable(EditorBrowsableState.Always),
    DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
    public int Note
    {
        get { return (int)GetValue(NoteProperty); }
        set { SetValue(NoteProperty, value); /* don't put anything more here */ }
    }

my WPF property

public static readonly DependencyProperty 
        NoteProperty = DependencyProperty.Register("Note",
        typeof(int), typeof(PatchRenderer),
        new PropertyMetadata(
            new PropertyChangedCallback(PatchRenderer.onNoteChanged)
            ));

    private static void onNoteChanged(DependencyObject d,
               DependencyPropertyChangedEventArgs e)
    {
        // this is the bug: calling the setter in the callback
        //((PatchRenderer)d).Note = (int)e.NewValue;

        // the following was wrongly placed in the Note setter.
        // it make sence to put it here.
        // this method is intended to display stars icons
        // to represent the Note
        ((PatchRenderer)d).UpdateNoteIcons();
    }