下载并保存文件/下载文件夹中的.pdf文件 - WP8 Silverlight

Question

直截了当：我想下载并保存.pdf文件，以便用户稍后可以在媒体库中看到它。

我正在寻找一种在Windows Phone 8 Silverlight中实现此目的的方法。

这是我现在正在使用的代码：

private void DownloadPDF(string url)
    {
        var client = new WebClient();
        client.OpenReadCompleted += client_OpenReadCompleted;

        this.FileName = Path.GetFileName(url);

        client.OpenReadAsync(new Uri(url));
    }

    async void client_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
    {
        // Save file:

        var buffer = new byte[e.Result.Length];
        await e.Result.ReadAsync(buffer, 0, buffer.Length);

        using (var storageFile = IsolatedStorageFile.GetUserStoreForApplication())
        {
            using (var stream = storageFile.OpenFile(this.FileName, FileMode.Create))
            {
                await stream.WriteAsync(buffer, 0, buffer.Length);
            }
        }

        // Open file:
        var local = ApplicationData.Current.LocalFolder;
        var pdffile = await local.GetFileAsync(this.FileName);
        Windows.System.Launcher.LaunchFileAsync(pdffile);

        var progressIndicator = new ProgressIndicator()
        {
            IsVisible = false
        };

        SystemTray.SetProgressIndicator(this, progressIndicator);
    }

非常感谢！