WP7: Why does a ListBox.ItemsPanel break my ElementName data binding?

Question

I have a Windows Phone 7 ListBox that binds to a list of integers. I am using the default MVVM Light template, so there is a ViewModel class that

Answer 1

This is a known problem with Silverlight 3. To work around this, wrap your DataTemplate in a UserControl:

    <UserControl x:Class="SilverlightApplication.MyUserControl">
        <Button Content="{Binding}">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="Click">
                    <cmd:EventToCommand Command="{Binding ElementName=ContentGrid, Path=DataContext.TestCommand}"
                                        CommandParameter="{Binding}" />
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </Button>
    </UserControl>

And use it instead:

<ListBox ItemsSource="{Binding MyData}">
    <ListBox.ItemTemplate>
        <DataTemplate>                        
            <local:MyUserControl />
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>