Get Index of a LongListSelector SelectedItem with JumpList and DataSource as List<AlphaKeyGroup<Artist>> where Artist is a custom class

Question

I have the below class ArtistAlbum:

    public class Artist
{
    public string ArtistName { get; set; }
}

This LonglistSelector belongs to the MusicPage.xaml and after getting the Index of the LongListSelector.SelectedItem, I would like to retrieve the details of the Artist Collection at the above retrieved Index at a different page and hence the use of GlobalVars. But, I'm not able to get the Index of the LongListSelector.

private void llsArtists_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    // Getting the index here from llsArtists.ItemsSource by using IndexOf
    // doesn't work and returns -1
    // Get the ID here and save it to GlobalVars._artistID;
    NavigationService.Navigate(new Uri("/ArtistDetail.xaml", UriKind.Relative));
}

The below method is responsible for getting the results into the collection.

void GetArtists()
    {

        this.Dispatcher.BeginInvoke(() =>
        {

            for (int i = 0; i < ml.Artists.Count; i++)
            {
                sourceArtists.Add(new Artist
                {
                    ArtistName = ml.Artists[i].Name.ToUpper(),
                });


                List<AlphaKeyGroup<Artist>> DataSource = AlphaKeyGroup<Artist>.CreateGroups(sourceArtists,
                      System.Threading.Thread.CurrentThread.CurrentUICulture,
                      (Artist s) => { return s.ArtistName; }, true);

                    llsArtists.ItemsSource = DataSource;

            }


        });
    }

Please see the image below for the ItemSource structure

Answer 1

This has solved my query:

As my ItemsSource was originally Artist but it was then converted to List<AlphaKeyGroup<Artist>>, I then selected my List<AlphaKeyGroup<Artist>> as the ItemsSource to get the .IndexOf by using the following:

1. I first got the Model.Name attribute of the e.AddedItems by using this void

    private void llsArtists_SelectionChanged(object sender, SelectionChangedEventArgs e)
   {
       // Getting the index here from llsArtists.ItemsSource by using IndexOf
       // doesn't work and returns -1
       // Get the ID here and save it to GlobalVars._artistID;
       var artist = (Artist)e.AddedItems[0];
       GetSelectedArtist(artist.ArtistName);
       //int selectedIndex = llsArtists.ItemsSource.IndexOf(llsArtists.SelectedItem as AlphaKeyGroup<Artist>);
       NavigationService.Navigate(new Uri("/ArtistDetail.xaml", UriKind.Relative));
   }
   

2. and then using LINQ, I iterated to get my SelectedItemIndex

But I believe it could also be retrieved by a simple .IndexOf replacing the ItemsSource as the AlphaKeyGroup source. (Haven't checked this yet)

public Artist GetSelectedArtist(string aName)
        {
            var result = (sourceArtists.Single(u => u.ArtistName == aName));
            var index = sourceArtists.IndexOf(result);
            GlobalVars._artistID = index;
            return result;
        }