用foreach UploadProgressChanged

Question

好吧，我有這樣的：

foreach (FileInfo fileinfo2 in Arquivos2) 
{ 
    label8.Text = "Enviando(NFe): " + fileinfo2.Name + "..."; 
    label8.Update(); 
    WebClient client = new WebClient(); 
    client.Credentials = new System.Net.NetworkCredential(usuario, senha); 
    client.UploadProgressChanged += new UploadProgressChangedEventHandler(UploadProgressCallback); 
    client.UploadFile(new Uri("ftp://" + ftp + "/" + caminho + "//nf//" + fileinfo2.Name), "STOR", @"C:\\NFe\" + fileinfo2.Name); 
    bar++; 
    backgroundWorker1.ReportProgress(bar); 
} 

它的做工精細，但我有：

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

，並沒有任何反應與progressBar2 ...

我怎麼可以更新我的progressBar2有一個uploadprogress？我無法使用UploadFile和UploadProgressChanged？

Answer 1

根據http://msdn.microsoft.com/en-us/library/system.net.webclient.uploadprogresschanged.aspx

此事件是每一個異步上傳使人進步次上調。

它僅由3個異步事件引發。您正在調用的版本是一種阻止方法，直到它完成並且不會返回進度事件纔會返回。