C#

IA : IUnknown
IB : IA
IC : IB

[ComImport, System.Security.SuppressUnmanagedCodeSecurity,
     Guid("00-this-is-valid-guid-000"),
     InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface IA
{
 method1();
}

<UserControl x:Class="Test.DateList"<br />
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"<br />
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"<br />
    xmlns:c="clr-namespace:Test"><br />
<DockPanel><br />
  <StackPanel><br />
    <RadioButton Checked="YMD"> Show YMD </RadioButton><br />
    <RadioButton Checked="MDY"> Show MDY </RadioButton><br />
  </StackPanel><br />
  <ListView Name="list"><br />
     <ListView.ItemTemplate><br />
        <DataTemplate><br />
           <TextBlock Text="{Binding Path=Date, Converter=???" /><br />
        </DataTemplate><br />
     </ListView.ItemTemplate><br />
  </ListView><br />
</DockPanel>

[ValueConversion(typeof(DateTime), typeof(String))]<br />
partial class DateList : UserControl, IValueConverter<br />
{<br />
   enum Form { YMD, MDY }<br />
   Form DateForm = YMD;<br />
   public DateList()<br />
   {<br />
       InitializeComponent();<br />
<br />
       // initialize the content of the ListView<br />
       List<DateTime> dates = new List<DateTime>();<br />
       for (int i=0;i<10;i++)<br />
           dates.Add(DateTime.Today + TimeSpan.FromDays(i));<br />
       list.ItemsSource = dates;<br />
   }<br />
  void YMD(object sender, RoutedEventArgs e)<br />
  {<br />
     DateForm = Form.YMD;<br />
     list.InvalidateVisual();<br />
  }<br />
  void MDY(object sender, RoutedEventArgs e)<br />
  {<br />
     DateForm = Form.MDY;<br />
     list.InvalidateVisual();<br />
  }<br />
  public object Convert(object value, Type targetType, object parameter, CultureInfo culture)<br />
  {<br />
      DateTime dt = (DateTime)value;<br />
      DateList dl = parameter as DateList;<br />
      if (dl != null)<br />
      {<br />
        switch (dl.DateForm)<br />
        {<br />
          case Form.YMD: return dt.ToString("yyyy/MM/dd");<br />
          case Form.MDY: return dt.ToString("MMM dd, yyyy");<br />
        }<br />
      }<br />
      return null;<br />
  }<br />
  public Object ConvertBack(object value, Type targetType, object parameter, CultureInfo ci) { return null; }<br />
}