silverlight - Silverlight 中的 MediaElement 问题

Question

我在使用 MediaElement 时遇到困难Windows Phone 7 的 Silverlight 中的控件。我的目标是在用户按下按钮时播放两种音调。我想出的这样做的方法是拥有一个 MediaElement对于每个音调。 (可能有更好的方法吗？)

<phone:PhoneApplicationPage 
    x:Class="MediaElementTest.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">

    <StackPanel x:Name="LayoutRoot" Background="Transparent">

            <MediaElement 
                x:Name="firstTone"
                MediaEnded="firstTone_MediaEnded"
                Source="{Binding FirstTone}" />
            <MediaElement 
                x:Name="secondTone"
                Source="{Binding SecondTone}" />
            <Button Content="Play" Click="Button_Click" />

    </StackPanel>

</phone:PhoneApplicationPage>

代码隐藏:

public partial class MainPage : PhoneApplicationPage
    {
        public Uri FirstTone
        {
            get
            {
                return new Uri("A.mp3", UriKind.Relative);
            }
        }

        public Uri SecondTone
        {
            get
            {
                return new Uri("B.mp3", UriKind.Relative);
            }
        }

        public MainPage()
        {
            InitializeComponent();
            LayoutRoot.DataContext = this;
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            firstTone.Stop();
            secondTone.Stop();

            firstTone.Play();
        }

        private void firstTone_MediaEnded(object sender, RoutedEventArgs e)
        {
            secondTone.Play();
        }
    }

当我单击按钮时，没有声音播放。为什么是这样？我究竟做错了什么？

Answer 1

不要使用 MediaElement为了这。而是添加对 Microsoft.Xna.Framework.dll 的引用(是的，即使在 Silverlight 项目中)然后使用 SoundEffect .

就像是:

using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;

using (var stream = TitleContainer.OpenStream("a.mp3"))
{
    var effect = SoundEffect.FromStream(stream);
    effect.Play();

    // This will pause while the first sound plays
    //  so they don't play over each other but as it also blocks!
    Thread.Sleep(effect.Duration);
}

using (var stream = TitleContainer.OpenStream("b.mp3"))
{
    var effect = SoundEffect.FromStream(stream);
    effect.Play();
}