private void setIconBinding() { string bindingPath = "SmallIcon"; bool useLargeIcons = Application.Current.FindResource("UseLargeIcons") as bool? ?? false; if (useLargeIcons) { bindingPath = "LargeIcon"; } Binding iconBinding = new Binding(bindingPath); iconBinding.Mode = BindingMode.OneWay; ToolbarIcon.SetBinding(Image.SourceProperty, iconBinding); }