I would like write an app where I can manipulate the currently playing song (from the Music app for example) such as jumping to the next song in playlist, restarting it or setting the volume up.
I searched the Windows SDK and tried all samples that seemed relevant to my problem, but I could not find anything that would give me a hint regarding how to do this.
So I would like to ask - How do I mute or change the master volume in my Metro (Windows 8) application?
Metro apps are not allowed to make changes to the system settings. So controlling the Master Volume is not possible from within the metro app. that's y Microsoft provides a settings charm where you can change the volume. the setting's charm is available in right side of your screen.
you can go through this link on MSDN for further clarification