如何在c＃中使用UWP下载文件

Question

I'm a beginner in programming, and I was wondering what the right way is to download files in UWP I now use this, but it only works like 50% of the time:

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();
    }
}

The exception is: "Unhandled exception at 0x750F6D7E (combase.dll in program.exe 0xC000027B; An application-internal exception has occurred (parameters: 0x16E73128, 0x00000001)."

Thanks in advance

Answer 1

There are two ways to do it.
First one is to use HttpClient as you do (this works well with small files)

Second one is to use BackgroundDownloader Class . That's recommended way

 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);
        }
    }