How do I make an image in ListBox DataTemplate clickable?

Question

I'm making a chat client for WP7 in which you can share photos.

We have a setup where a message appears in a little chat box with user's nickname, a StackPanel for an image (if a URL string is provided along with the message), and a StackPanel for the message text.

It'd be great if a user could tap directly on the image to see a larger version. However, I can't get any events to fire.

I've used the approach of changing a button's template to be just an image before (not in a data template though) and it's worked fine. But this DataTemplate (separate file from the full view) is not working.

How can I accomplish this? Is this doable in a ListBox, or am I stuck to the awkward Twitter style of having to select the whole message, then look at a full view of the image?

EDIT

I tried the GestureListener approach, but ran into a problem where it couldn't parse the event handler name and would just throw an exception when I ran the app.

My data templates are in separate XAML files. I assumed there wouldn't be any difference in defining each template in the same file as the PhoneApplicationPage. Is that correct?

<DataTemplate x:Name="LeftMessageTemplate">
    <Grid Margin="0,0,0,17" HorizontalAlignment="Stretch">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="70"></ColumnDefinition>
            <ColumnDefinition Width="*"></ColumnDefinition>
        </Grid.ColumnDefinitions>
        <Border Grid.Column="0" BorderThickness="3" BorderBrush="{StaticResource ChatPivotSubBrush}" Margin="0, 3, 9, 0" VerticalAlignment="Top">
            <Image Source="{Binding AvatarURL}" Height="60" Width="60" VerticalAlignment="Top"/>
        </Border>
        <Grid Grid.Column="1" Width="372" VerticalAlignment="Top">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto"></ColumnDefinition>
                <ColumnDefinition Width="*"></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <StackPanel Grid.Column="0" HorizontalAlignment="Right" Orientation="Horizontal" Background="Transparent">
                <Image Source="/my_chatclient;component/Images/chattheirspointercroppedwp7.png" VerticalAlignment="Top" Margin="0, 28, 0, 0" Height="19" Width="13"/>
                <StackPanel Background="{StaticResource ChatPivotMainBrush}" Width="Auto" HorizontalAlignment="Left" MinHeight="66" VerticalAlignment="Top" Margin="0, 3, 0, 0" Orientation="Horizontal">
                    <StackPanel Margin="4, 4, 4, 4">
                        <Button>
                            <Button.Template>
                                <ControlTemplate>
                                    <Image Source="{Binding PictureURLPreview}" VerticalAlignment="Top" MaxWidth="200"/>
                                </ControlTemplate>
                            </Button.Template>
                            <i:EventTrigger EventName="Click">
                                <GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding ViewPictureCommand, Mode=OneWay}" />
                            </i:EventTrigger>
                        </Button>
                    </StackPanel>
                    <StackPanel MaxWidth="340" Orientation="Vertical" Margin="12,12,12,12">
                        <TextBlock FontWeight="Bold" Foreground="{StaticResource ChatDarkerBlueBrush}" Text="{Binding CreatorNicknameLabel}" TextWrapping="NoWrap" Margin="0, 0, 0, 0"  FontSize="18" />
                        <TextBlock MaxWidth="316" Foreground="{StaticResource ChatDarkerBlueBrush}" Text="{Binding Text}" TextWrapping="Wrap" Margin="0,0,0,0" FontSize="16" />
                        <TextBlock Foreground="{StaticResource ChatDarkerBlueBrush}" FontWeight="Light" Text="{Binding CreatedAtLabel}" TextWrapping="Wrap" Margin="0, 0,0 ,0" FontSize="14" />
                    </StackPanel>
                </StackPanel>
            </StackPanel>
        </Grid>
    </Grid>
</DataTemplate>

Answer 1

If I understood it correct, here is a way to accomplish it. Add the image to a button with an event handler. Something like:

           <StackPanel Grid.Column="0" HorizontalAlignment="Right" Orientation="Horizontal" Background="Transparent">
            <Button Click="ShowLarger" BorderThickness="0">
                <Image Source="/my_chatclient;component/Images/chattheirspointercroppedwp7.png" VerticalAlignment="Top" Margin="0, 28, 0, 0" Height="19" Width="13"/>
            </Button>
            <StackPanel Background="{StaticResource ChatPivotMainBrush}" Width="Auto" HorizontalAlignment="Left" MinHeight="66" VerticalAlignment="Top" Margin="0, 3, 0, 0" Orientation="Horizontal">
                <StackPanel Margin="4, 4, 4, 4">
                    <Button>
                        <Button.Template>

Answer 2

While there's not a awful lot of information here, I would recommend you bind a event to the Image itself, rather than using a Button's ContentTemplate for it.

With the Silverlight Toolkit you can simply use their geatureservice, like this:

<Image Source="{Binding PictureURLPreview}" VerticalAlignment="Top" MaxWidth="200">
    <toolkit:GestureService.GestureListener>
        <toolkit:GestureListener>
            <i:EventTrigger EventName="Tap">
                <GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding ViewPictureCommand, Mode=OneWay}" />
            </i:EventTrigger>
        </toolkit>
    </toolkit:GestureService.GestureListener>
</Image>

Answer 3

Use the Tap-event:

<Image Tap="doYourThing ... />