HOW TO：使用腳本控制 MediaElement
更新：2007 年 11 月
本範例說明如何在 Storyboard 中使用 MediaTimeline 控制 MediaElement。
範例
在 Storyboard 中使用 MediaTimeline 控制 MediaElement 的執行時間時，功能就與其他 Timeline 物件 (如動畫) 完全相同。例如，MediaTimeline 會使用如 BeginTime 的 Timeline 屬性，指定何時啟動 MediaElement (開始播放媒體)。它也會使用 Duration 屬性指定 MediaElement 的作用中時間 (即播放媒體的持續時間)。如需在 Storyboard 使用 Timeline 物件的詳細資訊，請參閱腳本概觀。
這個範例顯示如何建立簡單的媒體播放程式，此程式會使用 MediaTimeline 控制播放。這個媒體播放程式有播放、暫停、繼續和停止按鈕。此外也有 Slider 控制項做為進度列。
下列範例會建立媒體播放程式的使用者介面 (UI)。
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
x:Class="SDKSample.MediaTimelineExample" >
<StackPanel Background="Black">
<MediaElement Name="myMediaElement" MediaOpened="Element_MediaOpened"
Width="260" Height="150" Stretch="Fill" />
<!-- Button controls for play, pause, resume, and stop. -->
<StackPanel HorizontalAlignment="Center" Width="260" Orientation="Horizontal">
<Image Name="PlayButton" Source="images\UI_play.gif" Margin="30,10,10,10" />
<Image Name="PauseButton" Source="images\UI_pause.gif" Margin="10" />
<Image Name="ResumeButton" Source="images\UI_resume.gif" Margin="10" />
<Image Name="StopButton" Source="images\UI_stop.gif" Margin="10" />
</StackPanel>
<!-- Ths slider shows the progress of the media. -->
<Slider Name="timelineSlider" Margin="5" Width="250" HorizontalAlignment="Center"/>
<StackPanel.Triggers>
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="PlayButton">
<EventTrigger.Actions>
<BeginStoryboard Name= "myBegin">
<Storyboard SlipBehavior="Slip">
<!-- The MediaTimeline controls the timing of the video and acts like other Timeline objects.
For example, although the video clip (numbers.wmv) lasts longer, playback ends after six
seconds because that is the duration of the MediaTimeline (Duration="0:0:6"). -->
<MediaTimeline Source="media\numbers.wmv" Storyboard.TargetName="myMediaElement"
BeginTime="0:0:0" Duration="0:0:6" CurrentTimeInvalidated="MediaTimeChanged" />
</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
<!-- These triggers impliment the functionality of the Pause, Resume
and Stop buttons.-->
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="PauseButton">
<EventTrigger.Actions>
<PauseStoryboard BeginStoryboardName="myBegin" />
</EventTrigger.Actions>
</EventTrigger>
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="ResumeButton">
<EventTrigger.Actions>
<ResumeStoryboard BeginStoryboardName="myBegin" />
</EventTrigger.Actions>
</EventTrigger>
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="StopButton">
<EventTrigger.Actions>
<StopStoryboard BeginStoryboardName="myBegin" />
</EventTrigger.Actions>
</EventTrigger>
</StackPanel.Triggers>
</StackPanel>
</Page>
<Page xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
x:Class="SDKSample.MediaTimelineExample" >
<StackPanel Background="Black">
<MediaElement Name="myMediaElement" MediaOpened="Element_MediaOpened"
Width="260" Height="150" Stretch="Fill" />
<!-- Button controls for play, pause, resume, and stop. -->
<StackPanel HorizontalAlignment="Center" Width="260" Orientation="Horizontal">
<Image Name="PlayButton" Source="images\UI_play.gif" Margin="30,10,10,10" />
<Image Name="PauseButton" Source="images\UI_pause.gif" Margin="10" />
<Image Name="ResumeButton" Source="images\UI_resume.gif" Margin="10" />
<Image Name="StopButton" Source="images\UI_stop.gif" Margin="10" />
</StackPanel>
<!-- Ths slider shows the progress of the media. -->
<Slider Name="timelineSlider" Margin="5" Width="250" HorizontalAlignment="Center"/>
<StackPanel.Triggers>
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="PlayButton">
<EventTrigger.Actions>
<BeginStoryboard Name= "myBegin">
<Storyboard SlipBehavior="Slip">
<!-- The MediaTimeline controls the timing of the video and acts like other Timeline objects.
For example, although the video clip (numbers.wmv) lasts longer, playback ends after six
seconds because that is the duration of the MediaTimeline (Duration="0:0:6"). -->
<MediaTimeline Source="media\numbers.wmv" Storyboard.TargetName="myMediaElement"
BeginTime="0:0:0" Duration="0:0:6" CurrentTimeInvalidated="MediaTimeChanged" />
</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
<!-- These triggers impliment the functionality of the Pause, Resume
and Stop buttons.-->
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="PauseButton">
<EventTrigger.Actions>
<PauseStoryboard BeginStoryboardName="myBegin" />
</EventTrigger.Actions>
</EventTrigger>
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="ResumeButton">
<EventTrigger.Actions>
<ResumeStoryboard BeginStoryboardName="myBegin" />
</EventTrigger.Actions>
</EventTrigger>
<EventTrigger RoutedEvent="Image.MouseDown" SourceName="StopButton">
<EventTrigger.Actions>
<StopStoryboard BeginStoryboardName="myBegin" />
</EventTrigger.Actions>
</EventTrigger>
</StackPanel.Triggers>
</StackPanel>
</Page>
下列範例會建立進度列的功能。
Imports System
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Namespace SDKSample
Partial Class MediaTimelineExample
Inherits Page
' When the media opens, initialize the "Seek To" slider maximum value
' to the total number of miliseconds in the length of the media clip.
Private Sub Element_MediaOpened(ByVal sender As Object, ByVal e As RoutedEventArgs)
timelineSlider.Maximum = myMediaElement.NaturalDuration.TimeSpan.TotalMilliseconds
End Sub 'Element_MediaOpened
Private Sub MediaTimeChanged(ByVal sender As Object, ByVal e As EventArgs)
timelineSlider.Value = myMediaElement.Position.TotalMilliseconds
End Sub 'MediaTimeChanged
End Class 'MediaTimelineExample
End Namespace 'SDKSample
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
namespace SDKSample
{
public partial class MediaTimelineExample : Page
{
// When the media opens, initialize the "Seek To" slider maximum value
// to the total number of miliseconds in the length of the media clip.
private void Element_MediaOpened(object sender, EventArgs e)
{
timelineSlider.Maximum = myMediaElement.NaturalDuration.TimeSpan.TotalMilliseconds;
}
private void MediaTimeChanged(object sender, EventArgs e)
{
timelineSlider.Value = myMediaElement.Position.TotalMilliseconds;
}
}
}
如需完整範例，請參閱媒體庫。
請參閱
工作
HOW TO：控制 MediaElement (播放、暫停、停止、音量和速度)