To me your binding syntax is incorrect. DataContext="{Binding MVM, Source={StaticResource MainViewModel}
means you should have a "MVM" PROPERTY in your MainViewModel class. In your case MVM is a method.
Try replacing your MVM method by a property. That might work.
Another way to do it, is to set
DataContext="{StaticResource MainViewModel}"
In that case, the MVM method will be obsolete (I did not try it on WinRT)