C# 无法在dot net应用程序中连接服务器

我正在开发一个应用程序，从FTP服务器读取文件，并在windows窗体上显示文件详细信息。虽然它在我的系统中工作得很好，但当我在客户机上执行时，它会抛出异常。请建议如何解决此问题。如果有人愿意，我们将通过邮件提供完整的源代码

    Dim arr() As String
    Dim request As FtpWebRequest = WebRequest.Create(ftppath)

    ProgressBar1.Value = ProgressBar1.Value + 10
    request.Credentials = New NetworkCredential(user, pass)

    request.UseBinary = False
    request.UsePassive = True
    request.KeepAlive = False
    ProgressBar1.Value = ProgressBar1.Value + 10
    request.Method = WebRequestMethods.Ftp.ListDirectoryDetails
    ProgressBar1.Value = ProgressBar1.Value + 10
    Dim response As FtpWebResponse = request.GetResponse()
    ProgressBar1.Value = ProgressBar1.Value + 10
    Dim responseStream As Stream = response.GetResponseStream()
    ProgressBar1.Value = ProgressBar1.Value + 30
    Dim reader As StreamReader = New StreamReader(responseStream)
    Dim lol As String

    Do
        lol = reader.ReadLine
        If Len(lol) < 1 Then Exit Do
        arr = Split(lol, vbNewLine)
        For i = 0 To UBound(arr)
            If Len(arr(i)) > 0 Then
                ListBox1.Items.Add(arr(i))
                TextBox1.Text = arr(i)  'just testing it on a textbox
            End If
        Next
    Loop
    ProgressBar1.Value = ProgressBar1.Value + 30
    MessageBox.Show("Directory List Complete, status {0}", response.StatusDescription)

    reader.Close()
    response.Close()

---

您是否尝试在客户计算机上通过命令行ftp？是的，它可以连接ftp服务器。异常情况未显示其抛出的位置。您可以提供完整代码吗？可能是防火墙程序阻止您的可执行文件访问Internet吗？@hpfs您可以共享您的邮件id吗

 ************* Exception Text **************
    System.Net.WebException: Unable to connect to the remote server
       at System.Net.FtpWebRequest.CheckError()
       at System.Net.FtpWebRequest.GetResponse()
       at Sparky.Form2.Button2_Click(Object sender, EventArgs e)
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)