asp.net - VB.NET中YouTube DirectUpload的BackgroundWorker？

Question

我正在尝试将服务器上的视频直接上传到YouTube。用户添加视频后，该视频将被复制到YouTube。

用户添加视频的操作应开始上载过程，这可能需要一段时间。该表单，即使是异步表单，也不应坐在那里等待它发生。它应该刚刚开始并允许用户继续前进，并相信它会在后台得到照顾。

为此，我尝试使用system.threading.backgroundworker。我希望这一过程将开始，并且Web应用程序将继续发展。不是。无论是异步还是完全回发，它都处于挂起状态，并在返回并更新lblmsg.text之前等待上载完成。

我应该采取其他方法来解决这个问题，以便用户可以启动上传过程，而不必等待它完成吗？到目前为止，这是我的代码:

Sub up_load(s As Object, e As EventArgs)
    Dim worker As BackgroundWorker = New BackgroundWorker

    worker.WorkerReportsProgress = True
    worker.WorkerSupportsCancellation = True
    AddHandler (worker.DoWork), AddressOf begin_upload

    'call this and move on?
    worker.RunWorkerAsync()

    lblmsg.Text = "Successfully initiated upload"

End Sub

Sub begin_upload(s As Object, e As DoWorkEventArgs)

    Dim request As New YouTubeRequest(settings)
    Dim vidupload As New Video()

    vidupload.Title = "My Big Test Movie"
    vidupload.Tags.Add(New MediaCategory("Nonprofit", YouTubeNameTable.CategorySchema))
    vidupload.Keywords = "church, jesus"
    vidupload.Description = "See the entire video"
    vidupload.YouTubeEntry.Private = False
    vidupload.YouTubeEntry.setYouTubeExtension("location", "Downers Grove, IL")
    vidupload.YouTubeEntry.MediaSource = New MediaFileSource("c:\users\greg\test3.asf", "video/x-ms-wmv")

    Dim createdVideo As Video = Request.Upload(vidupload)
End Sub

Answer 1

您可能需要研究Task Parallel Library，以便在代码中添加多线程。根据您提供的代码:

添加此导入语句

Imports System.Threading.Tasks

并使用以下简单语句替换所有backgroundworker逻辑:

    Dim uploadTask As Task = Task.Factory.StartNew(Sub()
                                                       Dim request As New YouTubeRequest(settings)
                                                       Dim vidupload As New Video()

                                                       vidupload.Title = "My Big Test Movie"
                                                       vidupload.Tags.Add(New MediaCategory("Nonprofit", YouTubeNameTable.CategorySchema))
                                                       vidupload.Keywords = "church, jesus"
                                                       vidupload.Description = "See the entire video"
                                                       vidupload.YouTubeEntry.Private = False
                                                       vidupload.YouTubeEntry.setYouTubeExtension("location", "Downers Grove, IL")
                                                       vidupload.YouTubeEntry.MediaSource = New MediaFileSource("c:\users\greg\test3.asf", "video/x-ms-wmv")

                                                       Dim createdVideo As Video = request.Upload(vidupload)
                                                   End Sub)

现在，您可以使用uploadTask在后台上传视频，并且您的UI线程将可以自由处理其他代码。如果要取消和进度报告，确实会更加复杂，但是顶部的链接应该可以帮助您入门。