vb.net中的HttpWebRequest代理

Question

该代理中的问题，但我要代码，如果代理失败，请返回以从列表框中选择新代理的启动代码，而无需停止我的程序，然后重新启动，现在如果一个代理失败，我又可以重新开始，请浪费时间，我希望你了解我。

私有子线程任务（作为IEnumerable（字符串）的lstProxies）

    'iam want code to go back here if proxy fail, and select new proxy from my listbox
    For Each s As String In lstProxies

        Dim request As HttpWebRequest

        Dim datastring As String
        Dim login As String = thelogin(lstProxies)
        Dim emails As String = TextBox1.Text

        ServicePointManager.DefaultConnectionLimit = 100
        CheckForIllegalCrossThreadCalls = False
        request = CType(WebRequest.Create("https://test.com"), HttpWebRequest)
        request.Proxy = New WebProxy(s, True)
        request.Method = "POST"
        request.CookieContainer = cookieJar
        'here is Erorr Could not connect to remote server proxy not work
        Using postStream As Stream = request.GetRequestStream()
            Dim byteArray As Byte() = System.Text.Encoding.UTF8.GetBytes("id=" & login + "&email=" & emails)
            postStream.Write(byteArray, 0, byteArray.Length)
        End Using
        Using stream = New StreamReader(request.GetResponse().GetResponseStream())
            datastring = stream.ReadToEnd()
        End Using




        If datastring.Contains("succesfully") Then
            MessageBox.Show("found")
        ElseIf datastring.Contains("fail") Then
            MessageBox.Show("fail")
        Else
            TextBox3.Text = ("none")

        End If
    Next


End Sub

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