Procedura: ricevere una notifica al completamento di una sequenza temporale
Aggiornamento: novembre 2007
L’evento Completed informa l’utente quando Timeline viene completata. Una sequenza temporale si considera completata dopo aver raggiunto la fine del periodo attivo e quando non verrà più riprodotta a meno non venga riavviata in modo interattivo. Si noti che il termine "completato" non corrisponde a "riproduzione arrestata": l’arresto di una sequenza temporale non attiva l'evento Completed (a differenza del passaggio al periodo di riempimento della sequenza temporale).
Esempio
Nell'esempio riportato di seguito, due oggetti Storyboard vengono utilizzati per creare una transizione di animazione tra due immagini, archiviate utilizzando oggetti ImageSource e visualizzate utilizzando un controllo Image. Uno storyboard riduce il controllo dell'immagine fino a farlo scomparire. Dopo essere stato completato, l’oggetto ImageSource precedente viene scambiato con l’altro oggetto ImageSource e con un secondo storyboard che espande il controllo dell'immagine fino a quando non ritorna a dimensione intera.
<!-- TimelineCompletedExample.xaml
This example creates an animated transition between
two images. When the user clicks the Start Transition button,
a storyboard shrinks an image until it disappears.
The Completed event is used to notify the class when this
storyboard has completed. The code behind file handles
this event by swapping the image and making it visible again.
-->
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
x:Class="SDKSample.TimelineCompletedExample"
WindowTitle="Timeline Completed Example"
Loaded="exampleLoaded">
<Page.Resources>
<!-- A simple picture of a rectangle. -->
<DrawingImage x:Key="RectangleDrawingImage">
<DrawingImage.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="White">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0,100,100" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing Brush="Orange">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="25,25,50,50" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingGroup>
</DrawingImage.Drawing>
</DrawingImage>
<!-- A simple picture of a cirlce. -->
<DrawingImage x:Key="CircleDrawingImage">
<DrawingImage.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="White">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0,100,100" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing>
<GeometryDrawing.Geometry>
<EllipseGeometry Center="50,50" RadiusX="25" RadiusY="25" />
</GeometryDrawing.Geometry>
<GeometryDrawing.Brush>
<RadialGradientBrush GradientOrigin="0.75,0.25" Center="0.75,0.25">
<GradientStop Offset="0.0" Color="White" />
<GradientStop Offset="1.0" Color="LimeGreen" />
</RadialGradientBrush>
</GeometryDrawing.Brush>
</GeometryDrawing>
</DrawingGroup>
</DrawingImage.Drawing>
</DrawingImage>
<!-- Define the storyboard that enlarges the image.
This storyboard is applied using code when
ZoomOutStoryboard completes. -->
<Storyboard x:Key="ZoomInStoryboardResource">
<DoubleAnimation
Storyboard.TargetName="AnimatedImageScaleTranform"
Storyboard.TargetProperty="ScaleX"
Duration="0:0:5" To="1" />
<DoubleAnimation
Storyboard.TargetName="AnimatedImageScaleTranform"
Storyboard.TargetProperty="ScaleY"
Duration="0:0:5" To="1" />
</Storyboard>
</Page.Resources>
<StackPanel Margin="20" >
<Border
BorderBrush="Gray" BorderThickness="2"
HorizontalAlignment="Center" VerticalAlignment="Center">
<!-- Displays the current ImageSource. -->
<Image
Name="AnimatedImage"
Width="200" Height="200"
RenderTransformOrigin="0.5,0.5">
<Image.RenderTransform>
<ScaleTransform x:Name="AnimatedImageScaleTranform"
ScaleX="1" ScaleY="1" />
</Image.RenderTransform>
</Image>
</Border>
<!-- This StackPanel contains buttons that control the storyboard. -->
<StackPanel Orientation="Horizontal" Margin="0,30,0,0">
<Button Name="BeginButton">Start Transition</Button>
<Button Name="SkipToFillButton">Skip To Fill</Button>
<Button Name="StopButton">Stop</Button>
<StackPanel.Triggers>
<!-- Begin the storyboard that shrinks the image. After the storyboard
completes, -->
<EventTrigger RoutedEvent="Button.Click" SourceName="BeginButton">
<BeginStoryboard Name="ZoomOutBeginStoryboard">
<Storyboard x:Name="ZoomOutStoryboard"
Completed="zoomOutStoryboardCompleted" FillBehavior="Stop">
<DoubleAnimation
Storyboard.TargetName="AnimatedImageScaleTranform"
Storyboard.TargetProperty="ScaleX"
Duration="0:0:5" To="0" FillBehavior="Stop" />
<DoubleAnimation
Storyboard.TargetName="AnimatedImageScaleTranform"
Storyboard.TargetProperty="ScaleY"
Duration="0:0:5" To="0" FillBehavior="Stop" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
<!-- Advances ZoomOutStoryboard to its fill period.
This action triggers the Completed event. -->
<EventTrigger RoutedEvent="Button.Click" SourceName="SkipToFillButton">
<SkipStoryboardToFill BeginStoryboardName="ZoomOutBeginStoryboard" />
</EventTrigger>
<!-- Stops the storyboard. This action does not
trigger the completed event. -->
<EventTrigger RoutedEvent="Button.Click" SourceName="StopButton">
<StopStoryboard BeginStoryboardName="ZoomOutBeginStoryboard" />
</EventTrigger>
</StackPanel.Triggers>
</StackPanel>
</StackPanel>
</Page>
// TimelineCompletedExample.xaml.cs
// Handles the ZoomOutStoryboard's Completed event.
// See the TimelienCompletedExample.xaml file
// for the markup that creates the images and storyboards.
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Navigation;
namespace SDKSample
{
public partial class TimelineCompletedExample : Page
{
private Storyboard zoomInStoryboard;
private ImageSource currentImageSource;
private ImageSource nextImageSource;
public TimelineCompletedExample()
{
InitializeComponent();
}
private void exampleLoaded(object sender, RoutedEventArgs e)
{
// Cache the zoom-out storyboard resource.
zoomInStoryboard =
(Storyboard) this.Resources["ZoomInStoryboardResource"];
// Cache the ImageSource resources.
currentImageSource =
(ImageSource) this.Resources["RectangleDrawingImage"];
nextImageSource =
(ImageSource) this.Resources["CircleDrawingImage"];
// Display the current image source.
AnimatedImage.Source = currentImageSource;
}
// Handles the zoom-out storyboard's completed event.
private void zoomOutStoryboardCompleted(object sender, EventArgs e)
{
AnimatedImage.Source = nextImageSource;
nextImageSource = currentImageSource;
currentImageSource = AnimatedImage.Source;
zoomInStoryboard.Begin(AnimatedImage, HandoffBehavior.SnapshotAndReplace);
}
}
}
Per ulteriori informazioni sugli eventi di temporizzazione, vedere Cenni preliminari sugli eventi di tempo.