c# - 如何在c#中使用UWP下载文件

Question

我是编程初学者，我想知道在 UWP 中下载文件的正确方法是什么我现在使用它，但它只有 50% 的时间有效:

public async Task StartDownload()
{
    try
    {
        StorageFile sf = await DownloadsFolder.CreateFileAsync(title.Text, CreationCollisionOption.GenerateUniqueName);
        downloadFolder = (await sf.GetParentAsync()).ToString();
        HttpClient client = new HttpClient();
        byte[] buffer = await client.GetByteArrayAsync(inputURL);
        using (Stream stream = await sf.OpenStreamForWriteAsync())
        {
            stream.Write(buffer, 0, buffer.Length);
        }
        path = sf.Path;
    }
    catch (Exception e)
    {
        MessageDialog dialog = new MessageDialog("Sorry, something went wrong...", "An error...");
        await dialog.ShowAsync();
    }
}

异常(exception)情况是:“0x750F6D7E 处的未处理异常(program.exe 0xC000027B 中的 combase.dll；发生应用程序内部异常(参数:0x16E73128、0x00000001)。”

提前致谢

Answer 1

有两种方法可以做到。
第一个是像你一样使用 HttpClient(这适用于小文件)

第二个是使用 BackgroundDownloader Class .这是推荐的方式

 private async void StartDownload_Click(object sender, RoutedEventArgs e)
    {
        try
        {
            Uri source = new Uri(inputURL);

            StorageFile destinationFile = await KnownFolders.PicturesLibrary.CreateFileAsync(
                title.Text, CreationCollisionOption.GenerateUniqueName);

            BackgroundDownloader downloader = new BackgroundDownloader();
            DownloadOperation download = downloader.CreateDownload(source, destinationFile);

            // Attach progress and completion handlers.
            HandleDownloadAsync(download, true);
        }
        catch (Exception ex)
        {
            LogException("Download Error", ex);
        }
    }