Binding to INotifyCollectionChanged event   

I am trying to bind a dependency property to an aggregate of a
collection. I've implemented a wrapper around a Dictionary that
implements INotifyCollectionChanged to fire the event when items are
added or removed.

Debugging through it I notice that there is nothing attached to the
event after I bind to it which I expected the SetBinding to do as I
don't know what delegate to bind to the event.

I've tried a test with just an ObservableCollection to see if I was
missing something but that doesn't work either.

How do I wire up the event to the binding to get my test to pass?

Here's my test code:

[TestClass()]
public class ObservableDictionaryTest : DependencyObject
{
    public class MaxDoubleConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object
parameter, System.Globalization.CultureInfo culture)
        {
            if (value is IEnumerable<double>)
            {
                return ((IEnumerable<double>)value).Max(); // using
Linq
            }

            throw new ArgumentException("Cannot covert " +
value.GetType() + " to IEnumerable<double>", "value");
        }

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

    public double Max
    {
        get { return (double)GetValue(MaxProperty); }
    }

    public static readonly DependencyProperty MaxProperty =
        DependencyProperty.Register("Max", typeof(double),
typeof(ObservableDictionaryTest), new PropertyMetadata(0.0));

    [TestMethod()]
    public void TestBindingToObservableCollection()
    {
        ObservableCollection<double> values = new
ObservableCollection<double>();
        values.Add(1.0);
        values.Add(2.0);
        values.Add(3.0);

        Binding b = new Binding();
        b.Converter = new MaxDoubleConverter();
        b.Source = values;
        b.Mode = BindingMode.OneWay;
        BindingOperations.SetBinding(this, MaxProperty, b);

        Assert.AreEqual(3.0, Max); // this works

        values.Add(4.0);
        Assert.AreEqual(4.0, Max); // this doesn't

        values.Remove(4.0);
        Assert.AreEqual(3.0, Max);
    }
}

date: Mon, 9 Jun 2008 06:36:37 -0700 (PDT)   author:   Some Bloke