Q:

toggle WP (7 ~ 7.8) user Ring Tone (Ring/vibrate)?

Is any way to access the current tone and toggle between tone/vibrate on Custom APP?
Some like
...
if isVibrate then
    ChangeToTone()
Else
    ChangeToVibrate()
End if

isVibrate = Not isVibrate
...

A:

No! The current SDK for windows phone does not give you access to this. Hopefully we might get it in a future release. 

