Question

I need to bind a Label to two ListBoxes. In order to do this I have set the SelectionChanged property of both ListBoxes to the same function:

<ListBox Name="ListBox1" SelectionChanged="UpdateSelectedItem" />
<ListBox Name="ListBox2" SelectionChanged="UpdateSelectedItem" />
<Label Name="DetailsLabel" DataContent="DefinedElsewhere" />

However I am having trouble finding what the selected item actually is. I have gone through all the properties of the sending object and the SelectionChangedEventArgs but I cannot find it. The ListBox is bound to an ObservableCollection of objects, and I would like the Label to display the properties of the last selected item, no matter from which ListBox it was selected. How do I find that?

private void UpdateSelectedItem(object sender, SelectionChangedEventArgs e)
{
     DetailsLabel.Content = ???;
}

Answer 1

You can read the selected item text doing something like:

ListBoxItem item = ((ListBox)sender).SelectedItem as ListBoxItem;
String itemText = (item != null) ? item.Content.ToString() : String.Empty;

You have to cast the SelectedItem property to the type of object you have in the list.
In this example I’ve used ListBoxItem.