c# - UWP MediaPlaybackList 添加 MediaSource 工作太慢

Question

MediaPlaybackList 有问题，如下所示:

playbackList = new MediaPlaybackList();
playbackList.AutoRepeatEnabled = true;
for (int i = 0; i < songs.Count();i++)
{    
    var song = songs.ElementAt(i);    
    var source = MediaSource.CreateFromStorageFile(
        await StorageFile.GetFileFromPathAsync(song.File));
    source.CustomProperties[TrackIdKey] = null;
    source.CustomProperties[TitleKey] = song.Title;
    source.CustomProperties[AlbumArtKey] = song.AlbumArtUri;
    source.CustomProperties[AuthorKey] = song.Author;
    source.CustomProperties[TrackNumber] = (uint)(i+1);
    playbackList.Items.Add(new MediaPlaybackItem(source));
}

当我尝试将 MediaSource 添加到我的播放列表时，它花费了太多时间。 700 首歌曲大约需要 3 分钟才能开始播放。也许还有另一种方法可以将 MediaSource 添加到 MediaPlaybackList 中，这样效果更快？

Answer 1

使用 IRandomAccessStreamReference。这样它只需要在到达 Item 时加载文件，速度要快得多。

不过您必须编写自己的抽象类。可能看起来有点像这样:

public class MyStreamReference : IRandomAccessStreamReference
{
    private string path;

    public MyStreamReference(string path)
    {
        this.path = path;
    }

    public IAsyncOperation<IRandomAccessStreamWithContentType> OpenReadAsync()
        => Open().AsAsyncOperation();

    // private async helper task that is necessary if you need to use await.
    private async Task<IRandomAccessStreamWithContentType> Open()
        => await (await StorageFile.GetFileFromPathAsync(path)).OpenReadAsync();
}