9

在 c#/wpf 中，我在窗口中添加了进度条和媒体元素。这个想法是进度条显示媒体元素中播放了多少。

我用以下 xaml 进行了尝试：

<Window x:Class="TestApp.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="627" Width="889">
    <Grid>
    <MediaElement Margin="152,8,140,41" Name="mediaElement1" MediaEnded="mediaElement1_MediaEnded" Visibility="Hidden" />
    <ProgressBar Height="23" Margin="152,8,10,0" Name="mp3PlayingProgressBar" VerticalAlignment="Top" Foreground="DarkBlue" Maximum="{Binding Path=NaturalDuration.TimeSpan.TotalSeconds, Mode=OneWay, ElementName=mediaElement1}" Value="{Binding Path=Position.TotalSeconds, Mode=OneWay, ElementName=mediaElement1}" />
    </Grid>
</Window>

我试图将最大值和值属性绑定到媒体元素。但是，例如，当我将 mp3 加载到 mediaelement 中时，进度条没有任何反应。（音乐正在播放，因此 mp3 已加载并正确播放）。

我更喜欢通过绑定来做到这一点。

我在这里做错了什么？

4

5 回答 5

11

那是因为媒体没有打开，因此进度条不知道最大值。试试这个...

将以下事件用于 MediaOpened，并将 MouseLeftButtonUp 用于您的进度条或滑块。我试过了，它工作得很好。

public partial class AudioPage : Page
{
    TimeSpan _position;
    DispatcherTimer _timer = new DispatcherTimer();

    public AudioPage()
    {
        InitializeComponent();
        _timer.Interval = TimeSpan.FromMilliseconds(1000);
        _timer.Tick += new EventHandler(ticktock);
        _timer.Start();
    }

    void ticktock(object sender, EventArgs e)
    {
        sliderSeek.Value = media.Position.TotalSeconds;
    }

    // Executes when the user navigates to this page.
    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
    }

    private void Play_Click(object sender, RoutedEventArgs e)
    {
        media.Play();
    }

    private void Pause_Click(object sender, RoutedEventArgs e)
    {
        media.Pause();
    }

    private void Stop_Click(object sender, RoutedEventArgs e)
    {
        media.Stop();
    }

    private void media_MediaOpened(object sender, RoutedEventArgs e)
    {
        _position = media.NaturalDuration.TimeSpan;
        sliderSeek.Minimum = 0;
        sliderSeek.Maximum = _position.TotalSeconds;
    }

    private void sliderSeek_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        int pos = Convert.ToInt32(sliderSeek.Value);
        media.Position = new TimeSpan(0, 0, 0, pos, 0);
    }
}

关联的 XAMl 如下...

<Grid x:Name="LayoutRoot" Background="#FFFFE8E8">
    <Grid.RowDefinitions>
        <RowDefinition Height="220*" />
        <RowDefinition Height="75*" />
    </Grid.RowDefinitions>
    <MediaElement Height="189" HorizontalAlignment="Left" Margin="12,12,0,0" Name="media" VerticalAlignment="Top" Width="399" Source="anyfile.mp3" AutoPlay="True" MediaOpened="media_MediaOpened" />
    <StackPanel Orientation="Horizontal" Grid.Row="1" Height="30" Margin="12,8,163,37">
        <TextBlock Text="Volume" VerticalAlignment="Center"></TextBlock>
        <Slider Margin="2" Maximum="1" Minimum="0" Width="102" Value="{Binding Path=Volume, Mode=TwoWay, ElementName=media}"></Slider>
        <TextBlock Text="{Binding ElementName=media, Path=Volume, Mode=OneWay, StringFormat=0.00}" VerticalAlignment="Center" />
    </StackPanel>
    <StackPanel Orientation="Horizontal" Grid.Row="1" Height="30" Margin="26,47,163,-2">
        <TextBlock Text="Seek" VerticalAlignment="Center"></TextBlock>
        <Slider Margin="2" Width="104" Name="sliderSeek" MouseLeftButtonUp="sliderSeek_MouseLeftButtonUp"></Slider>
        <TextBlock Text="{Binding ElementName=sliderSeek, Path=Value, StringFormat=0}" VerticalAlignment="Center"></TextBlock>
    </StackPanel>
    <StackPanel Orientation="Horizontal" Grid.Row="1" Height="30" Margin="266,8,12,37">
        <Button Name="Play" Content="Play" Margin="2" Click="Play_Click" />
        <Button Name="Pause" Content="Pause" Margin="2" Click="Pause_Click" />
        <Button Name="Stop" Content="Stop" Margin="2" Click="Stop_Click" />
    </StackPanel>
</Grid>
于 2010-10-30T10:26:42.943 回答
3

我尝试绑定这些值并达到此目的，但没有成功：

<ProgressBar 
    x:Name="testProgressBar" Minimum="0" 
    Maximum="{Binding NaturalDuration.TimeSpan.TotalSeconds, ElementName=mediaPlayer}" 
    Value="{Binding Position.TotalSeconds, ElementName=mediaPlayer, Mode=OneWay}" />

太糟糕了，它不起作用。
恐怕您需要设置一个计时器。
就像是：

*.xaml

<ProgressBar x:Name="testProgressBar" />

*。CS

    public MainWindow()
    {
        InitializeComponent();
        DispatcherTimer timer = new DispatcherTimer();
        timer.Interval = TimeSpan.FromSeconds(1);
        timer.Tick += timer_Tick;
        timer.Start();
    }
    private void timer_Tick(object sender, EventArgs e)
    {
        if (mediaPlayer.Source != null && mediaPlayer.NaturalDuration.HasTimeSpan)
        {
            testProgressBar.Minimum = 0;
            testProgressBar.Maximum = mediaPlayer.NaturalDuration.TimeSpan.TotalSeconds;
            testProgressBar.Value = mediaPlayer.Position.TotalSeconds;
        }
    }

亲切的问候，
蒂莫。

于 2014-04-08T23:37:09.177 回答
1

Rahul 示例的 WPF 版本，在滑动条时添加了媒体位置的实时变化。

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        _timer.Interval = TimeSpan.FromMilliseconds(1000);
        _timer.Tick += new EventHandler(ticktock);
        _timer.Start();

        Open(@"filename.mp3");
    }
    public void Open(string fileName)
    {
        var uriPath = "file:///" + fileName.Replace("\\", "/");
        media.Source=new Uri(uriPath);
    }

    TimeSpan _position;
    DispatcherTimer _timer = new DispatcherTimer();

    void ticktock(object sender, EventArgs e)
    {
        if (!sliderSeek.IsMouseCaptureWithin)
            sliderSeek.Value = media.Position.TotalSeconds;
    }

    private void Play_Click(object sender, RoutedEventArgs e)
    {
        media.Play();
    }

    private void Pause_Click(object sender, RoutedEventArgs e)
    {
        media.Pause();
    }

    private void Stop_Click(object sender, RoutedEventArgs e)
    {
        media.Stop();
    }

    private void media_MediaOpened(object sender, RoutedEventArgs e)
    {
        _position = media.NaturalDuration.TimeSpan;
        sliderSeek.Minimum = 0;
        sliderSeek.Maximum = _position.TotalSeconds;
    }

    private void sliderSeek_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {           
        int pos = Convert.ToInt32(sliderSeek.Value);
        media.Position = new TimeSpan(0, 0, 0, pos, 0);
    }

    private void sliderSeek_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
    {
        if (sliderSeek.IsMouseCaptureWithin)
        {
            int pos = Convert.ToInt32(sliderSeek.Value);
            media.Position = new TimeSpan(0, 0, 0, pos, 0);
        }
    }
}
于 2016-02-09T09:17:24.897 回答
0

看看这个例子 - 他使用滑块而不是进度条......

将预览行为附加到 WPF 滑块控件

http://jobijoy.blogspot.com/2009/07/attaching-preview-behavior-to-wpf.html

于 2010-10-30T11:36:16.963 回答
0

GitHub 中有一个名为Gu.Wpf.Media的包装库，可以处理所有问题MediaElement并带来更多问题。

它支持通过开箱即用的绑定来绑定到Position属性。TwoWay无需为计时器烦恼。

于 2017-01-17T14:08:18.690 回答