Windows Media Player 11 SDK Playlists and Media ItemsĀ
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Playlists and Media Items
A playlist is a set of media items. A Playlist object can manipulate the Media objects that represent those items.
Retrieving Media Items
For an existing playlist, you can read the Playlist**.count** property to determine how many media items are in the playlist, and you can get a reference to the Media object corresponding to a specific item using the Playlist**.item** property.
The following C# example retrieves an object reference to a specific media item. (Throughout this topic, the variable pList is a reference to a Playlist object.)
currMedia = pList.Item(0);
The following C# example retrieves the names of all the media items in a playlist and puts them in a ListBox named lstOutput.
for (j=0; j < pList.count; j++) { strItemName = pList.get_Item(j).name; lstOutput.Items.Add(strItemName); }
Adding Items to a Playlist
You can add a media item to the end of a playlist or at a specific position in a playlist, using the Playlist**.appendItem** and Playlist**.insertItem** methods.
Throughout this topic, the Player object was defined in the following manner:
AxWMPLib.AxWindowsMediaPlayer Player; using WMPLib;
The following C# example demonstrates both techniques by adding the current media item to a playlist named "BluesTest", first at the end and then at the beginning of the playlist.
IWMPPlaylistCollection pListColl; IWMPPlaylistArray pListArray; IWMPPlaylist pList; // Initialize the Media object IWMPMedia currMedia = Player.currentMedia; if(currMedia != null) { // Retrieve the playlist collection pListColl = Player.playlistCollection; // Retrieve a playlist array containing // playlists named BluesTest pListArray = pListColl.getByName("BluesTest"); // Retrieve the first element with this name from the // array. pList = pListArray.Item(0); // Add the current item to the end, and then, the beginning // of the specified playlist. pList.appendItem(currMedia); pList.insertItem(0, currMedia); }
When you create a new, empty playlist by using the PlaylistCollection**.newPlaylist** method, you can add media items to it by repeatedly calling the Playlist**.appendItem** method.
Manipulating Media Items in a Playlist
You can change the position of a media item in the playlist by using the Playlist**.moveItem** method. You specify the item by its current index, and then you specify the new index. The following C# example moves an item from index 5 to index 0 within a playlist.
// Move the 6th item to the beginning // of the specified playlist. pList.moveItem(5, 0);
You can remove a media item from the playlist by using the Playlist**.removeItem** method. Note that if the removed item was not the final item in the playlist, the index values of the subsequent items change. The following C# example removes the specified item.
// Remove the currently playing item from the // specified playlist. pList.removeItem(currMedia);
Note Users can change the contents of a playlist outside of your application. Whenever you manipulate the items in a playlist, you should monitor and handle the playlist-related events of the Windows Media Player control to ensure that your code works correctly. These events are Player.CurrentPlaylistChange and Player.PlaylistChange.
See Also
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