Hey, I'm trying to implement a WPF program that runs in the background, but is only brought up when a certain keyboard shortcut is pushed

This is similar to Quicksilver for mac or the dashboard for mac (ie, hit F12 and a dashboard pops up, hit F12 again and it disappears).

I already have the WPF program, I just need to know how to do this, is it possible? Thanks for your help.