将进度条绑定到WPF中的中介 [英] Binding a progressbar to a mediaelement in wpf

问题描述

在c#/wpf中，我在窗口中添加了一个进度条和中介元素.想法是，进度栏将显示中介元素中播放了多少内容.

In c#/wpf I added a progressbar and mediaelement to my window. The idea was that progressbar is displaying how much is been played in the mediaelement.

我尝试了以下xaml:

I tried it with the following xaml:

<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Maximum和Value属性绑定到中介元素.但是，当我将mp3加载到中介元素中时，进度条什么也没有发生.(正在播放音乐，因此mp3已加载并正确播放).

I tried to bind the Maximum and Value property to the mediaelement. But when I load a mp3 for example into the mediaelement, nothing happends with the progressbar. (The music is playing so the mp3 is loaded and playing correctly).

我更喜欢通过绑定来做到这一点.

I prefer to do this with a binding.

我在这里做什么错了?

推荐答案

这是因为未打开媒体，因此进度条不知道最大值.试试这个...

That is because Media is not opened and hence the progress bar is not aware of the maximum value. Try this...

对MediaOpened使用以下事件，对进度栏或滑块使用MouseLeftButtonUp.我试过了，效果很好.

Use the following events for MediaOpened, and MouseLeftButtonUp for your progress bar or slider. I tried it, and it works just fine.

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XAMl如下...

The associate XAMl is as follows...

<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>

这篇关于将进度条绑定到WPF中的中介的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！