C# UWP BackgroundDownloader即使在PC上也会冻结 stringurl=”http://any_urls"; MediaPlayer=新的MediaPlayer（）； 公共主页（） { 初始化组件（）； Debug.WriteLine（“下载已启动”）； var file=Download（）.Result；// 开始下载时忘记调用“AsTask”方法

不能有异步构造函数

string url = "http://any_urls";
    MediaPlayer player = new MediaPlayer();

    public MainPage()
    {
        InitializeComponent();

        Debug.WriteLine("Download started");
        var file = Download().Result; // <-- Here's where it stucks
        Debug.WriteLine("Download finished");

        player.Source = MediaSource.CreateFromStorageFile(file);
        player.Play();
    }

    private async Task<StorageFile> Download()
    {
        StorageFile destinationFile = await ApplicationData.Current.LocalFolder.CreateFileAsync(
            "data.mp3", CreationCollisionOption.GenerateUniqueName);
        BackgroundDownloader downloader = new BackgroundDownloader();
        DownloadOperation download = downloader.CreateDownload(new Uri(url), destinationFile);
        await download.StartAsync();
        return destinationFile;
    }

public主页（）
{
this.InitializeComponent（）；
}
已加载专用异步无效页（对象发送方，RoutedEventArgs e）
{
Debug.WriteLine（“下载已启动”）；
var file=await downloadsync（）；
Debug.WriteLine（“下载完成”）；
player.Source=MediaSource.CreateFromStorageFile（文件）；
player.Play（）；
}
私有异步任务下载异步（）
{
StorageFile destinationFile=Wait ApplicationData.Current.LocalFolder.CreateFileAsync(
“data.mp3”，CreationCollisionOption.GenerateUniqueName）；
BackgroundDownloader downloader=新的BackgroundDownloader（）；
DownloadOperation download=downloader.CreateDownload（新Uri（url），destinationFile）；
等待下载.StartAsync（）.AsTask（）；
返回目标文件；
}

public MainPage()
{
    this.InitializeComponent();
}

private async void Page_Loaded(object sender, RoutedEventArgs e)
{
    Debug.WriteLine("Download started");
    var file = await DownloadAsync();
    Debug.WriteLine("Download finished");

    player.Source = MediaSource.CreateFromStorageFile(file);
    player.Play();
}

private async Task<StorageFile> DownloadAsync()
{
    StorageFile destinationFile = await ApplicationData.Current.LocalFolder.CreateFileAsync(
        "data.mp3", CreationCollisionOption.GenerateUniqueName);
    BackgroundDownloader downloader = new BackgroundDownloader();
    DownloadOperation download = downloader.CreateDownload(new Uri(url), destinationFile);
    await download.StartAsync().AsTask();
    return destinationFile;
}