绑定到ObservableCollection <string>的Silverlight TabControl在更改集合时不更新

Question

带有TabControl的Silverlight 3应用程序使用IValueConverter绑定到ObservableCollection.应用程序启动时初始绑定工作(转换器调用).对绑定集合的更改,Clear()或Add()不会反映在未调用的TabControl ...转换器中.

注意:绑定的ListBox反映了对绑定集合的更改,而TabControl则没有.

想法？

/ JHD

---

XAML绑定......

<UserControl.Resources>
    <local:ViewModel x:Key="TheViewModel"/>
    <local:TabConverter x:Key="TabConverter" />
</UserControl.Resources>
<StackPanel DataContext="{StaticResource TheViewModel}">
    <ListBox ItemsSource="{Binding Classnames}" />
    <controls:TabControl x:Name="TheTabControl" 
        ItemsSource="{Binding Classnames, Converter={StaticResource TabConverter}, ConverterParameter=SomeParameter}"/>
    <Button Click="Button_Click" Content="Change ObservableCollection" />
</StackPanel>

---

ViewModel ......

namespace DatabindingSpike
{
    public class ViewModel
    {
        private ObservableCollection<string> _classnames = new ObservableCollection<string>();

        public ViewModel()
        {
            _classnames.Add("default 1 of 2");
            _classnames.Add("default 2 of 2");
        }

        public ObservableCollection<string> Classnames
        {
            get { return _classnames; }
            set { _classnames = value; }
        }
    }
}

---

转换器(完整性)......

namespace DatabindingSpike
{
    public class TabConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            var source = value as ObservableCollection<string>;
            if (source == null)
                return null;

            var param = parameter as string;
            if (string.IsNullOrEmpty(param) || param != "SomeParameter")
                throw new NotImplementedException("Null or unknow parameter pasased to the tab converter");

            var tabItems = new List<TabItem>();
            foreach (string classname in source)
            {
                var tabItem = new TabItem
                                  {
                                      Header = classname,
                                      Content = new Button {Content = classname}
                                  };
                tabItems.Add(tabItem);
            }

            return tabItems;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

Answer 1

暴露

public ObservableCollection<TabItem> Classnames
{
    get { return _classnames; }
    set { _classnames = value; }
}

如果您调试 valueconverter，您会发现它没有像您想象的那样被调用。