WPF: Implementing a MediaPlayer Audio / Video Seek

问题:

I am currently working on an MP3 player (in a WPF application) with a WPF MediaPlayer and basically, I want to implement a Song Seeker which moves along with the current playing song.

I already implemented a song slider (from Sacha Barber's application) and it works when the user drags the seeker manually (as in, the song continues from that position) but I cannot figure out how to make the seeker move according to the current position in the song.

Trouble is I don't think there is a way to check when the Position property of the MediaPlayer has changed, so I'm stumped as to how I should implement this feature.

Any ideas on how to go about such an issue?

[Update]

As regards incrementing the seeker with a timer, I actually thought of using the reason I didn't try it yet is because I think there is a better way to implement this using the MediaTimeline...but I'm yet to figure out how.

回答1:

ARISE answer! and serve your master

OK, I've figured out how to work this. I'm sure I'm not doing it the completely correct way but it does work.

Here is the code-behind of a WPF application, with a Pause/Play button.

public partial class Main : Window
{
    MediaPlayer MPlayer;
    MediaTimeline MTimeline;

    public Main()
    {
        InitializeComponent();

        var uri = new Uri("C:\\Test.mp3");
        MPlayer = new MediaPlayer();
        MTimeline = new MediaTimeline(uri);
        MTimeline.CurrentTimeInvalidated += new EventHandler(MTimeline_CurrentTimeInvalidated);
        MPlayer.Clock = MTimeline.CreateClock(true) as MediaClock;
        MPlayer.Clock.Controller.Stop();
    }

    void MTimeline_CurrentTimeInvalidated(object sender, EventArgs e)
    {
        Console.WriteLine(MPlayer.Clock.CurrentTime.Value.TotalSeconds);
    }

    private void btnPlayPause_Click(object sender, RoutedEventArgs e)
    {
        //Is Active
        if (MPlayer.Clock.CurrentState == ClockState.Active)
        {
            //Is Paused
            if (MPlayer.Clock.CurrentGlobalSpeed == 0.0)
                MPlayer.Clock.Controller.Resume();
            else //Is Playing
                MPlayer.Clock.Controller.Pause();
        }
        else if (MPlayer.Clock.CurrentState == ClockState.Stopped) //Is Stopped
            MPlayer.Clock.Controller.Begin();
    }
}

The trick is that once you set the clock of a MediaPlayer, it becomes clock controlled, thus the use of MPlayer.Clock.Controller to do all of the controlling :)

回答2:

Never played with media player but assuming you know the length of song could you not setup a timer that ticks every second while the song is playing. Therefore for every tick just increment the seeker in relation to how long the song is in total.

Song is 100 seconds long. Therefore every second/tick is worth 1 percent of total progress.

You'd have to stop the timer when pausing song etc...

回答3:

MediaElement has a position property which you could use for this: http://msdn.microsoft.com/en-us/library/system.windows.controls.mediaelement.position.aspx

回答4:

Have you checked out the WPF MediaKit yet?