wp7音乐播放器

Question

I am trying to develop a music player application in wp. Right now, I can retrieve the list of songs from the MediaLibrary and add it to a listbox.

MediaLibrary lib = new MediaLibrary();
var SongName = (from m in lib.Songs select m.Name).ToList();
listBox1.ItemsSource = SongName;

The list is getting populated and I am accessing the ListBox items using event

listBox1_SelectionChanged 

I want the selected item to be converted to the type Song, so that i can play that using a MediaPlayer class.

normal typecasting such as

Song x = (Song)listBox1.SelectedItem;

How do I make it work?

Answer 1

You're selecting the song name (string) as the data source type. As you've seen, you can't convert a string to a Song type simply by explicitly casting it (you could perform a search in the MediaLibrary if you really wanted to keep the string type). Alternatively you can bind the Song object itself to your ListBox.

MediaLibrary lib = new MediaLibrary();
var SongName = lib.Songs.ToList();
listBox1.ItemsSource = SongName;

Then in your event handler

Song x = listBox1.SelectedItem as Song;
if(x != null)
   MediaPlayer.Play(x);

If you really want to only have the string type in the ListBox , you can perform a search like this in your SelectedChanged event. (You'd have to make lib a class level variable)

Song x = lib.Songs.Where(s => s.Name == listbox1.SelectedItem.ToString()).FirstOrDefault();

The main problem with this method is that if there are two tracks with the same name, only the first is returned. You'll need a way of differentiating them but the other properties, such as Artist , has been removed from your data source (because you only used the Song's Name property).