Issue binding command parameter in Silverlight

I can't seem to get this to work right. Basically, I have an ObservableCollection that is bound to a list. Inside this collection, I have an object that I need to use to pass as a variable to a Command when it's executed. My plan was to pass this as CommandParameter, but I can't get it to work. The object is actually an Enum value, but I can't get it to work with anything but static text. Below is the code, it's using a MVVM concept using Interactivity(wi)and blend开发者_高级运维's dll(sl). The property is public on the ListItem, and does implement INotifyPropertyChanged.

Thanks.

<ListBox ItemsSource="{Binding Path=MyList}" ScrollViewer.VerticalScrollBarVisibility="Disabled">
                    <wi:Interaction.Triggers>
                        <wi:EventTrigger EventName="SelectionChanged">
                            <sl:InvokeDataCommand  CommandParameter="{Binding MyList.ListItem.Property}" Command="{Binding Source={StaticResource Locator}, Path=MyTestPage.TestExecute}" />
                        </wi:EventTrigger>
                    </wi:Interaction.Triggers>

...

        <ListBox x:Name="listBox" ItemsSource="{Binding Path=MyList}" ScrollViewer.VerticalScrollBarVisibility="Disabled">
    <wi:Interaction.Triggers>                         
    <wi:EventTrigger EventName="SelectionChanged">
    <sl:InvokeDataCommand  CommandParameter="{Binding ElementName=listBox, Path=SelectedItem.Property}" Command="{Binding Source={StaticResource Locator}, Path=MyTestPage.TestExecute}" />
</wi:EventTrigger>
</wi:Interaction.Triggers>

How about doing this? You want to bind to the selectedItem, not ?

MyList is your ObservableCollection ?