media player questions

I'm making a media player in wpf using c#. I had 3 questions.

1. I tried making a seeker

   XAML:

   <Slider Name="timelineSlider" Margin="40,91,26,0" ValueChanged="SeekToMediaPosition" Height="32" VerticalAlignment="Top" />
   

   Code:

   private void Element_MediaOpened(object sender, EventArgs e)
   {
       timelineSlider.Maximum = ply.NaturalDuration.TimeSpan.TotalMilliseconds;
   }
   
   private void SeekToMediaPosition(ob开发者_开发知识库ject sender, RoutedPropertyChangedEventArgs<double> e)
   {
       int SliderValue = (int)timelineSlider.Value;
       TimeSpan ts = new TimeSpan(SliderValue, SliderValue, SliderValue, SliderValue, SliderValue);
       ply.Position = ts;
   }
   

   When I run the program, I open the mp3 and play it but the seeker won't move. When I click on the seeker to move it to a certain position, the song stops playing but the seeker moves. What's the problem and how do I fix it?

2. How do I create a volume increase/decrease bar?

3. How can I open several mp3s and queue them up like a playlist?

Answer to #2 you will need to keep a ordered collection of files to play, and listen to mediaStopped event, and play the next file in the collection.

I am going to assume that you are playing the MP3 using the MediaElement control? If so your seeker (sometimes called a scrubber) can bind to the Position property of the MediaElement.

<MediaElement x:Name="_media"  />
<Slider Name="timelineSlider" 
        Margin="40,91,26,0" 
        Height="32" 
        VerticalAlignment="Top"
        Value="{Binding Path=Position.TotalMilliseconds, Mode=TwoWay, ElementName=_media}" />

If you want to create volume slider you can use a similar method by binding to the Volume Property, per the MSDN document the volume is a value between 0 and 1.

<Slider Name="_volumeSlider"
        Minimum="0"
        Maximum="1"
        Value="{Binding Path=Volume, Mode=TwoWay, ElementName=_media}" />

Regarding playing multiple files you'll want to adopt an approach similar to what LnDCobra indicated in their answer.