主题：请教串口问题

下面这段代码的功能是电话号码1占线，自动拨打电话2，请大家帮忙看一下错在那里了

Dim kj As String = e.sender.name
Dim dr As DataRow
dr = DataTables("人员表").Find("控件名称 = '"& kj &"'")
If dr IsNot Nothing Then
Dim dh1 As String = dr("电话号码1")
Dim dh2 As String = dr("电话号码2")

Ports("COM1").Open()
Ports("COM1").Write("ATD+'"& dh1 &"'" & vbCrLf)
If instr(1,buffer , "BUSY", vbTextCompare) Then
Buffer = ""
Ports("COM1").Write("ATD+'"& dh2 &"'" & vbCrLf)
End If
End If

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请帮我改改代码

dim buffer as string

Dim kj As String = e.sender.name
Dim dr As DataRow
dr = DataTables("人员表").Find("控件名称 = '"& kj &"'")
If dr IsNot Nothing Then
Dim dh1 As String = dr("电话号码1")
Dim dh2 As String = dr("电话号码2")

Ports("COM1").Open()
Ports("COM1").Write("ATD+'"& dh1 &"'" & vbCrLf)
If instr(1,buffer , "BUSY", vbTextCompare) Then
Buffer = ""
Ports("COM1").Write("ATD+'"& dh2 &"'" & vbCrLf)
End If
End If

这样改了之后，虽然不报错，但他只能拨通第一个电话，无法跳转来拨通第二个电话

Dim kj As String = e.sender.name
Dim dr As DataRow
Static Buff As String = "busy"
dr = DataTables("人员表").Find("控件名称 = '"& kj &"'")
If dr IsNot Nothing Then
    Dim dh1 As String = dr("电话号码1")
    Dim dh2 As String = dr("电话号码2")
   
    Ports("COM1").Open()
    Ports("COM1").Write("ATD+'"& dh1 &"'" & vbCrLf)
    If instr(buff , "BUSY") = 1 Then

        Buff = ""
        Ports("COM1").Write("ATD+'"& dh2 &"'" & vbCrLf)
    End If
End If

代码改成这个也不管用啊

Dim Buff As String = "OK"
Dim s As String
dr = DataTables("人员表").Find("控件名称 = '"& kj &"'")
If dr IsNot Nothing Then
    Dim dh1 As String = dr("电话号码1")
    Dim dh2 As String = dr("电话号码2")
   
    Ports("COM1").Open()
    Ports("COM1").Write("ATD+'"& dh1 &"'" & vbCrLf)
s = Ports("COM1").ReadExisting()
Forms("准东线").Controls("Label3").Text = s

 

    If s="ok" Then
Ports("COM1").Write("ATH0" & vbCrLf)

        Buff = ""
        Ports("COM1").Write("ATD+'"& dh2 &"'" & vbCrLf)
    End If

电话号码1正常能拨通，S也显示等于“ok”，但是还是不能拨通电话号码2，真搞糊涂哦

1   Dim kj As String = e.sender.name
2   Dim dr As DataRow
3   Dim s As String
4   dr = DataTables("人员表").Find("控件名称 = '"& kj &"'")
5   If dr IsNot Nothing Then
6   Dim dh1 As String = dr("电话号码1")
7   Dim dh2 As String = dr("电话号码2")
   
8    Ports("COM1").Open()
9    Ports("COM1").Write("ATD+'"& dh1 &"'" & vbCrLf)
10    s = Ports("COM1").ReadExisting()
11    Forms("准东线").Controls("Label3").Text = s
12   MessageBox.Show(s)
13    Ports("COM1").Write("ATH0" & vbCrLf)
14    MessageBox.Show(s)
    If s="ok" Then 

MessageBox.Show(s="ok")

        Ports("COM1").Write("ATD+'"& dh2 &"'" & vbCrLf)
    End If
End If

 

只能执行到第14句，前面全部正确，s="ok",从第15句开始不执行