Question

I making a soundboard as an exercise for myself. I want to parse the URIs from an XML file and bind them to a single mediaelement. I have eight buttons that I want to trigger different audio files. I only have one page so I can’t use NavigationContext.QueryString to pass an attribute id as a querystring to LINQ. How can I change the attribute depending on what button I press?

Here’s the code:

Audio Class:

public class AudioClass
{
    string audio;

    public string Audio 
    {
        get { return audio; }
        set { audio = value; }
    }

}

Code:

public partial class MainPage : PhoneApplicationPage
{
    string name = "C";

    public MainPage()
    {
        InitializeComponent();    
    }

    protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
    {
        XDocument audioPlayer = XDocument.Load("Audio.xml");

        var aani = (from audio in audioPlayer.Descendants("Note")
                    where audio.Attribute("id").Value == name
                    select new AudioClass
                    {
                        Audio = (string)audio.Element("url").Value

                    }).SingleOrDefault();

        player.Source = new Uri(aani.Audio, UriKind.Relative);

        base.OnNavigatedTo(e);
    }

    private void C_Key_Click(object sender, RoutedEventArgs e)
    {
        player.Play();
    }

    private void D_Key_Click(object sender, RoutedEventArgs e)
    {
        player.Play();
    }

And XAML:

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="41,-8,-17,8">
        <Button x:Name="C_key" Content="" HorizontalAlignment="Left" Height="220" Margin="8,0,0,8" Style="{StaticResource C}" VerticalAlignment="Bottom" Width="75" Click="C_Key_Click"/>
        <Button x:Name="D_key" Content="" HorizontalAlignment="Left" Height="220" Margin="87,0,0,8" Style="{StaticResource D}" VerticalAlignment="Bottom" Width="75" Click="D_Key_Click"/>
        <Button x:Name="E_key" Content="" HorizontalAlignment="Left" Height="220" Margin="166,0,0,8" Style="{StaticResource E}" VerticalAlignment="Bottom" Width="75" Click="E_Key_Click"/>
        <Button x:Name="F_key" Content="" HorizontalAlignment="Left" Height="220" Margin="245,0,0,8" Style="{StaticResource F}" VerticalAlignment="Bottom" Width="75" d:LayoutOverrides="Width" Click="F_Key_Click"/>
        <Button x:Name="G_key" Content="" Height="220" Margin="324,0,305,8" Style="{StaticResource G}" VerticalAlignment="Bottom" Click="G_Key_Click"/>
        <Button x:Name="A_key" Content="" HorizontalAlignment="Right" Height="220" Margin="0,0,226,8" Style="{StaticResource A}" VerticalAlignment="Bottom" Width="75" Click="A_Key_Click"/>
        <Button x:Name="B_key" Content="" HorizontalAlignment="Right" Height="220" Margin="0,0,147,8" Style="{StaticResource B}" VerticalAlignment="Bottom" Width="75" Click="B_Key_Click"/>
        <Button x:Name="C2_key" Content="" HorizontalAlignment="Right" Height="220" Margin="0,0,68,8" Style="{StaticResource C2}" VerticalAlignment="Bottom" Width="75" Click="C2_Key_Click"/>
        <MediaElement Height="120" HorizontalAlignment="Left" Margin="8,6,0,0" Name="player" VerticalAlignment="Top" Width="160" Source="{Binding Audio}" Volume="1" AutoPlay="False"/>
        </Grid>

Answer 1

1. Extract SetPlayerSource() from OnNavigatedTo().

2. Use SetPlayerSource() in generic button click event handler.

   protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
   {
       SetPlayerSource();
   
       base.OnNavigatedTo(e);
   }
   
   private void SetPlayerSource()
   {
       XDocument audioPlayer = XDocument.Load("Audio.xml");
   
       var aani = (from audio in audioPlayer.Descendants("Note")
                   where audio.Attribute("id").Value == name
                   select new AudioClass
                   {
                       Audio = (string)audio.Element("url").Value
   
                   }).SingleOrDefault();
   
       player.Source = new Uri(aani.Audio, UriKind.Relative);
   }
   
   private void ButtonKey_Click(object sender, RoutedEventArgs e)
   {
       var buttonName = (sender as Button).Name;
       var underscorePos = buttonName.IndexOf('_');
       name = buttonName.Substring(0, underscorePos);
       SetPlayerSource();
       player.Play();
   }