namespace WpfApplication1
{
  public partial class MainWindow : Window
  {
    public MainWindow()
    {
      InitializeComponent();
    }
    protected void btnAnimatelblMessage_Click(object sender, RoutedEventArgs args)
    {
      DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();
      dblAnim.From = 40;
      dblAnim.To = 200;
      dblAnim.AutoReverse = true;
      dblAnim.RepeatBehavior = new RepeatBehavior(TimeSpan.FromSeconds(30));
      dblAnim.Duration = new Duration(TimeSpan.FromSeconds(4));
      lblHeight.BeginAnimation(Label.HeightProperty, dblAnim);
    }
    protected void btnAnimatelblTransparency_Click(object sender, RoutedEventArgs args)
    {
      DoubleAnimation dblAnim = new DoubleAnimation();
      dblAnim.From = 1.0;
      dblAnim.To = 0.0;
      dblAnim.Duration = new Duration(TimeSpan.FromSeconds(10));
      lblTransparency.BeginAnimation(Label.OpacityProperty, dblAnim);
    }
  }
}

The old Cod block
namespace WpfApplication1
{
  public partial class MainWindow : Window
  {
    public MainWindow()
    {
      InitializeComponent();
    }
    protected void btnAnimatelblMessage_Click(object sender, RoutedEventArgs args)
    {
      DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();DoubleAnimation dblAnim = new DoubleAnimation();
      dblAnim.From = 40;
      dblAnim.To = 200;
      dblAnim.AutoReverse = true;
      dblAnim.RepeatBehavior = new RepeatBehavior(TimeSpan.FromSeconds(30));
      dblAnim.Duration = new Duration(TimeSpan.FromSeconds(4));
      lblHeight.BeginAnimation(Label.HeightProperty, dblAnim);
    }
    protected void btnAnimatelblTransparency_Click(object sender, RoutedEventArgs args)
    {
      DoubleAnimation dblAnim = new DoubleAnimation();
      dblAnim.From = 1.0;
      dblAnim.To = 0.0;
      dblAnim.Duration = new Duration(TimeSpan.FromSeconds(10));
      lblTransparency.BeginAnimation(Label.OpacityProperty, dblAnim);
    }
  }
}