I finally found one hack and if you know a better way, please tell me in the comment which one it is \ud83d\ude42<\/p>\n

My solution is to use the RichTextBlock’s tapped event and its GetPositionFromPoint method<\/strong>. This method returns a TextPointer for a given position of your RichTextBlock. This TextPointer object has a Parent property which is the TextElement (Run, Underline, Span, etc…) the user clicked on : exactly what we want !<\/p>\n

My Xaml then look like this :
\n[xml]<RichTextBlock IsTextSelectionEnabled="False"
\n Margin="30"
\n Width="600"
\n TextAlignment="Justify"
\n FontSize="40"
\n TextWrapping="Wrap"
\n Tapped="UIElement_OnTapped">
\n <Paragraph>
\n <Run Text="Cupcake ipsum dolor. Sit amet I love croissant fawork" \/>
\n <Run Text=". " \/><\/p>\n

<Underline x:Name="LinkToInfiniteSquare"
\n Foreground="#FFFF1BF5">
\n <Run Text="I love ice cream, to write very long text " \/>
\n <Run Text="and to take some screenshots." \/>
\n <\/Underline><\/p>\n

<Run Text="A Chocolate ice cream souffl\u00e9 pastry. " \/><\/p>\n

<Underline x:Name="LinkToMyBlog"
\n Foreground="#FFFF1BF5">
\n <Run Text="Bear claw chocolate tart brownie apple pie." \/>
\n <\/Underline><\/p>\n

<\/Paragraph>
\n<\/RichTextBlock><\/p>\n

[\/xml]<\/p>\n

The last part is to walk trough the parents of the clicked\/touched element to find out its Underline parent, read its name and launch the correct action<\/strong>.<\/p>\n

[csharp]
\nprivate void UIElement_OnTapped(object sender, TappedRoutedEventArgs e)
\n{
\n var richTB = sender as RichTextBlock;
\n var textPointer = richTB.GetPositionFromPoint(e.GetPosition(richTB));<\/p>\n

var element = textPointer.Parent as TextElement;
\n while (element != null && !(element is Underline))
\n {
\n if (element.ContentStart != null
\n && element != element.ElementStart.Parent)
\n {
\n element = element.ElementStart.Parent as TextElement;
\n }
\n else
\n {
\n element = null;
\n }
\n }<\/p>\n

if (element == null) return;<\/p>\n

var underline = element as Underline;
\n if (underline.Name == "LinkToInfiniteSquare")
\n {
\n Launcher.LaunchUriAsync(new Uri("http:\/\/www.infinitesquare.com"));
\n }
\n else if (underline.Name == "LinkToMyBlog")
\n {
\n Launcher.LaunchUriAsync(new Uri("http:\/\/www.jonathanantoine.com"));
\n }<\/p>\n

}<\/p>\n

[\/csharp]<\/p>\n

By the way, I can not use a TextBlock element because it does not have the GetPositionFromPoint method.<\/p>\n