Dim s As SystemState
s = New SystemState(SystemProperty.PhoneIncomingCall)
AddHandler s.Changed, AddressOf phonemute
 
    Public Sub phonemute(ByVal sender As Object, ByVal args As ChangeEventArgs)
        If SystemState.PhoneIncomingCall = True Then
        phone_mute()
        Else
        set_vol(vol)
        End If
    End Sub

Nur Wissen ist Macht.