Q:

How can I prompt the user for a value in response to a RightTapped event? 

I need to prompt the user for textual input when they right-click or -tap a grid in a GridView.  How do I do that?  Do I need to create a custom user control or is there some way to use a Popup for that? 

A:

Take a look at the Callisto library that includes a lightweight flyout control.