Custom Usercontrol - Bindings or Codebehind

Visibility="{Binding Path=Show, Converter={cnv:BoolToVisibilityConverter}, UpdateSourceTrigger=PropertyChanged, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ctl:MyControl}}}"

public bool Show
{
     get { return (bool)GetValue(ShowProperty); }
     set { SetValue(ShowProperty, value); }
}

public static readonly DependencyProperty ShowProperty = DependencyProperty.Register
( "Show", typeof(bool), typeof(MyControl), new PropertyMetadata(OnShowChanged));

private static void OnShowChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
  //Pseudo
  theControl.Visibility = (bool)e.NewValue;
}