使用BackgroundWorker和更新UI

Question

Private _Proxies As New List(Of String) 
Private _Array As New List(Of String) 

Private Sub btnLeech_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Leech_btn.Click 
    Worker.RunWorkerAsync(_Array) 
End Sub 

'Open a bunch of new threads to download sources of webpages 
Private Sub Fetch(ByVal sender As System.Object, _ 
           ByVal e As System.ComponentModel.DoWorkEventArgs) Handles Worker.DoWork 
    Dim websiteUri As Uri = Nothing 
    Dim Website As String 
    For I = 0 To _Array.ToList.Count - 1 
     Website = _Array(I) 
     Using wc As Net.WebClient = New Net.WebClient 
      AddHandler wc.DownloadStringCompleted, AddressOf SourceDownloaded 
      If Uri.TryCreate(Website, UriKind.Absolute, websiteUri) Then 
       wc.DownloadStringAsync(New Uri(Website)) 
       Threading.Thread.Sleep(250) 
      Else 
       If Notify.Checked = True Then 
        TrayIcon.ShowBalloonTip(1, "Invalid website", "There was a invalid site in the list." & Website.ToString, ToolTipIcon.Error) 
        Me.TrashSite_list.Items.Add(Website) 
       Else 
        Me.TrashSite_list.Items.Add(Website) 
       End If 
      End If 
     End Using 
    Next 
End Sub 
'Grab the proxies from the webpages 
Private Sub SourceDownloaded(ByVal sender As Object, ByVal e As Net.DownloadStringCompletedEventArgs) 
    Dim strRegex As String = "\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\:[0-9]{1,5}\b" 
    Dim myRegexOptions As RegexOptions = RegexOptions.None 
    Dim myRegex As New Regex(strRegex, myRegexOptions) 
    Dim frm As New Proxies 
    Dim i As Integer 
    My.Settings.Proxies = New StringCollection 
    If e.Error Is Nothing Then 
     For Each myMatch As Match In myRegex.Matches(e.Result) 
      If myMatch.Success Then 
       Try 
        i += i 
        _Proxies.Add(myMatch.ToString) 
        Worker.ReportProgress(i) 
       Catch ex As WebException 
        MessageBox.Show(
         ex.ToString, 
         ErrorToString, 
         Windows.Forms.MessageBoxButtons.OK) 
       End Try 
      End If 
     Next 
    End If 
End Sub 

Private Sub Worker_ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles Worker.ProgressChanged 
    Proxy_list.Items.AddRange(_Proxies.ToArray) 
     Proxy2_lbl.Text = "Proxies: " & Proxy2_list.Items.Count 
    Proxy_lbl.Text = "Proxies: " & Proxy2_list.Items.Count 
End Sub 

这是我的代码，我希望它用它更新UI，但我不确定如何去做。我正在寻找一个评论的例子，所以我可以理解它。到目前为止，我已经在几个网站上发布了，每个人都会告诉我该怎么做，或给我一个例子，但没有人会告诉我该怎么做！他们希望我知道代码的作用，但如果我知道它做了什么，你真的认为我会问问题吗？无论如何，回到主题：

这是我想要完成的。当我点击Leech_btn时，它将我所有网站从Website_list添加到名为“Array”的数组中。然后它以数组作为参数运行背景工作。后台工作人员从列表中下载网站的字符串并将其移至SourceDownloaded进行过滤。 （它从网站中删除所有代理）然后它应该在Proxy_list中显示代理，但这是我遇到问题的地方。我该怎么办？

Answer 1

，如果我理解正确，问题是在

Dim Proxies() As String = My.Resources.SiteList6.Split(vbNewLine) 
Proxy_list.Items.AddRange(Proxies) 

这是因为在不同的线程的UI和工人。你可以补充一点：

Private Delegate Sub UpdateListDelegate(byval itemName() as string) 
Private Sub UpdateList(byval itemName() as string) 
    If Me.InvokeRequired Then 
     Me.Invoke(New UpdateListDelegate(AddressOf UpdateList), itemName) 
    Else 
     ' UpdateList 
     ' add list add code 
     Proxy_list.Items.AddRange(itemName) 
    End If 
End Sub 

在代码中，有

UpdateList(Proxies) 

替换 “Proxy_list.Items.AddRange（代理）” 见vb.net: listbox.items.add() throws exception in same class，类似的问题。