Windows Media Player 11 SDK Playlists and Media Items 

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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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