Can't get ListBox and UpdateTarget to work

Question

Here are the relevant parts of the XAML file:

xmlns:local="clr-namespace:BindingTest"
<ListBox x:Name="myList"
         ItemsSource="{Binding Source={x:Static local:MyClass.Dic},
                               Path=Keys,
                               Mode=OneWay,
                               UpdateSourceTrigger=Explicit}">
</ListBox>

MyClass is a public static class and Dic is a static public property, a Dictionary.

At a certain point I add items to the Dictionary and would like the ListBox to reflect the changes.
This is the code I thought about using but it doesn't work:

BindingExpression binding;
binding = myList.GetBindingExpression(ListBox.ItemsSourceProperty);
binding.UpdateTarget();

This code instead works:

myList.ItemsSource = null;
myList.ItemsSource = MyClass.dic.Keys;

I would prefer to use UpdateTarget, but I can't get it to work.
What am I doing wrong?

Answer 1

Binding of items is handled rather differently than standard binding of DependencyPropertys in WPF (specifically, by ItemsControls).

I think you want something like the following:

var itemsView = CollectionViewSource.GetDefaultView(myListBox.ItemsSource);
itemsView.Refresh()

It is in fact the ICollectionView object that you want to refresh. This effectively is the object that manages the collection binding for you. See the MSDN page for more info.