Como: Seguir um Storyboard sincronamente

O exemplo a seguir mostra como usar o método SeekAlignedToLastTick de um Storyboard para procurar qualquer posição em uma animação por storyboard de forma síncrona.

Exemplo

A marcação XAML para o exemplo é a seguinte:

<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation" 
  xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="SDKSample.SeekStoryboardSynchronouslyExample">
  <StackPanel Margin="20" >

    <Rectangle Name="myRectangle"
      Width="10" Height="20" Fill="#AA3333FF" HorizontalAlignment="Left" >
      <Rectangle.Triggers>
        <EventTrigger RoutedEvent="Rectangle.Loaded">
          <BeginStoryboard Name="myBeginStoryboard">
            <Storyboard Name="myStoryboard" Duration="0:0:4">
              <DoubleAnimation 
                Storyboard.TargetName="myRectangle" 
                Storyboard.TargetProperty="Width" 
                Duration="0:0:4" From="10" To="500"/>
            </Storyboard>

          </BeginStoryboard>
        </EventTrigger>
      </Rectangle.Triggers>
    </Rectangle>

    <!-- Use this slider to seek to different points of the Storyboard Duration 
         (in milliseconds). -->
    <Slider Name="SeekSlider" ValueChanged="OnSliderValueChanged" Height="Auto" 
    Width="500" Minimum="0" Maximum="4000" HorizontalAlignment="Left" />

    <!-- TextBlock displays the current time position of the Storyboard in milliseconds. -->
    <TextBlock Name="PositionTextBlock"/>
  </StackPanel>
</Page>

A seguir vemos o código usado junto com o XAML acima.

using System;
using System.Media;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media.Animation;

namespace SDKSample
{

    public partial class SeekStoryboardSynchronouslyExample : Page
    {
        private void OnSliderValueChanged(object sender, RoutedEventArgs e)
        {
            int sliderValue = (int)SeekSlider.Value;

            // The SeekAlignedToLastTick method should be used to seek a Storyboard synchronously.
            myStoryboard.SeekAlignedToLastTick(myRectangle, new TimeSpan(0, 0, 0, 0, sliderValue), TimeSeekOrigin.BeginTime);
            PositionTextBlock.Text = sliderValue.ToString();
        }
    }

}