private void _kinect_UserCreated(object sender, KinectUserEventArgs e)
{
Core.User kinect_user = _kinect.GetUser(e.User.Id);
var xnaUser = new User.User(kinect_user, Content,
new Size(graphics.PreferredBackBufferWidth, graphics.PreferredBackBufferHeight));
_users.Add(xnaUser);
}