如何在c#中使用UWP下载文件

Question

我是编程的初学者,我想知道在UWP中下载文件的正确方法我现在使用它,但它只能在50%的时间内工作:

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();
    }
}

例外情况是:"0x750F6D7E处的未处理异常(program.exe 0xC000027B中的combase.dll;发生了应用程序内部异常(参数:0x16E73128,0x00000001)."

提前致谢

Answer 1

有两种方法可以做到这一点.
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类.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);
        }
    }