VB6写的一个端口批量扫描器

Private Sub cmdStart_Click()
     Dim i As Long
    Dim j As Integer
    Dim k As Long, l As Long
    Dim t As String, ts As String, tip As String
    ts = txtList1.Text
    t = " "
    j = Int(txtPort.Text)
    If j < 1 Or j > 65535 Then
        MsgBox "检查端口号之于0-65535之间", vbExclamation, "端口错误"
    End If '
    Dim c As Long
    txtList2.Text = ""
    cmdStart.Enabled = False
    cmdStop.Enabled = True
    k = 0
    l = 0
    Do Until t = ""
        k = k 1
        If st = True Then
            cmdStart.Enabled = True
            st = False
            Exit Do
        End If
        t = GetStr(ts, "", vbCrLf, i)
        
        c = 0
        If Len(t) >= 4 Then '如果不是空的
            tip = GetStr(t, "", txtsp.Text)
            'tip = GetStr(tip, vbCrLf, "")
            tip = Replace(tip, Chr(10), "")
            tip = Replace(tip, Chr(13), "")
            If Client1.State <> sckClosed Then Client1.Close
           ' MsgBox Client1.State & vbCrLf & tip & ":" & j
            Client1.RemoteHost = tip
            Client1.RemotePort = j
            Client1.Connect tip, j
            Do Until Client1.State = 7
                DoEvents
                PauseTime 10
                c = c 1
                If c > 10 Then
                    GoTo a
                End If
            Loop
            If Client1.State = sckConnected Then
                l = l 1
                If txtList2.Text = "" Then
                    txtList2.Text = tip
                    Else: txtList2.Text = txtList2.Text & vbCrLf & tip
                End If
a:
                Client1.Close
            End If
        End If
        Lbl1.Caption = "已扫：" & k - 1 & "条 | 连接上：" & l & "条"
     Loop
     MsgBox "扫描结束", vbInformation
     cmdStart.Enabled = True
     cmdStop.Enabled = False
End Sub