Question

我有：

 foreach (FileInfo fileinfo in Arquivos)
               {
                   float zz = (float)fileinfo.Length;
                   zz = (zz / 1024f) / 1024f;
                   label8.Text = "sending: " + fileinfo.Name + "("+zz.ToString("0.0")+"MB)...";
                   label8.Update();
                   WebClient client = new System.Net.WebClient();
                   client.Credentials = new System.Net.NetworkCredential(usuario, senha);
                   client.UploadProgressChanged += new UploadProgressChangedEventHandler(UploadProgressCallback);
                   client.UploadFile(new Uri("ftp://" + ftp + "/" + caminho + "//" + fileinfo.Name), "STOR", pasta + mes + fileinfo.Name);
                   bar++;

                   backgroundWorker1.ReportProgress(bar);
               }

我需要创建一个UploadProgressChanged，所以我有：

client.UploadProgressChanged += new UploadProgressChangedEventHandler(UploadProgressCallback);

和

 private void UploadProgressCallback(object sender, UploadProgressChangedEventArgs e)
       {
           progressBar2.Value = e.ProgressPercentage;
           progressBar2.Update();
       }

UploadProgressChanged不适用于UploadFile，只是UploadfileAsync，但我每次都需要发送1个文件。如何将UploadFile更改为UploadFileAsync并每次发送一个文件？

Answer 1

如果您一次只能发送1个文件，那么为什么还要关注使用Async？您似乎也在使用后台工作人员来完成所有工作。

你是不是最好为每个要上传的文件启动'任务'，并使用一次只允许一个任务的调度程序将它们踢掉？

请参阅：http://msdn.microsoft.com/en-us/library/ee789351.aspx

通过这种方式，您可以在简化任务的同时使用一些较新的Task和异步方法。

基于进一步分析，如果您想异步运行它们，但一次只能执行一次：

    private AutoResetEvent _fileUploadedEvent = new AutoResetEvent(false);
    private void DoUploadBackgroundWorker()
    {
        foreach (var file in files)
        {
            client.WhenUploaded += (s, e) =>
                {
                    // This signals the AutoResetEvent that it can continue
                    _fileUploadedEvent.Set();
                };
            client.UploadAsync();
            // This will keep ticking over every 15 milliseconds to check if the
            // AutoResetEvent has been triggered
            while (_fileUploadedEvent.WaitOne(15)) { }
            // We get here when it's been triggered (which means the file was uploaded)
            // So we can update the progressbar here and then move onto the next file.
        }
    }

它需要扩展，并且这些类并不完全正确，因为我刚刚将它们组合在一起，但它应该提供足够的材料来启动你的方向。

使用Foreach上传FileFileAsync

1 个答案: