运行时错误8018? [英] run time error 8018?

问题描述

运行时错误8018:
该操作仅在端口打开时有效.

调试时说Mscomm1.output = 6
我是vb的新手..
我的代码...

run time error 8018:
operation valid only when the port is open.

when debuggin it says Mscomm1.output = 6
im a newbie in vb..
my code...

Dim hwdc As Long
Dim startcap As Boolean

Private Sub Command10_Click()
Dim sdata2 As Long ' Holds our incoming data
MSComm1.Input = sdata2
Label1.DataField = CLng(sdata2)
End Sub

Private Sub MSComm1_OnComm()
Dim sData As String ' Holds our incoming data
Dim lHighByte As Long   ' Holds HighByte value
Dim lLowByte As Long    ' Holds LowByte value
Dim lByte As Long       ' Holds the Byte result

' If comEvReceive Event then get data and display
If MSComm1.CommEvent = comEvReceive Then
   sData = MSComm1.Input ' Get data
    lHighByte = Asc(Mid$(sData, 1, 1)) ' get 1st byte
     lLowByte = Asc(Mid$(sData, 2, 1))  ' Get 2nd byte
   lByte = JoinHighLow(lHighByte, lLowByte)
    Label1.Caption = CStr(lByte)
    DrawScale lByte
End If

' Fire Rx Event Every Two Bytes
MSComm1.RThreshold = 2

' When Inputting Data, Input 2 Bytes at a time
MSComm1.InputLen = 2

' 2400 Baud, No Parity, 8 Data Bits, 1 Stop Bit
MSComm1.Settings = "2400,N,8,1"

' Make sure DTR line is low to prevent Stamp reset
MSComm1.DTREnable = False

'  Use COM9
MSComm1.CommPort = 1

' Open the port
MSComm1.PortOpen = True

End Sub
Private Function JoinHighLow(lHigh As Long, lLow As Long) As Long
JoinHighLow = (lHigh * &H100) Or lLow
End Function
Private Sub DrawScale(lVal As Long)
Picture1.Cls
Picture1.Line (0, 0)-(lVal, Picture1.ScaleHeight), vb3DShadow, BF
End Sub
Private Sub Command11_click()
Dim PinNumber As Variant
PinNumber = Text2.DataField
MSComm1.Output = Chr$(PinNumber) 'Chr$(255) &
End Sub
Private Sub Command2_click()
MSComm1.Output = Chr$(3)
End Sub
Private Sub Command3_Click()
MSComm1.Output = 4
End Sub
Private Sub Command1_click()
MSComm1.Output = 1
End Sub
Private Sub Command4_Click()
MSComm1.Output = 2
End Sub
Private Sub Command5_Click()
MSComm1.Output = 9
End Sub
Private Sub Command6_Click()
MSComm1.Output = 6
End Sub
Private Sub Command7_Click()
MSComm1.Output = 7
End Sub
Private Sub Command8_Click()
MSComm1.Output = 8
End Sub
Private Sub Command9_Click()
MSComm1.Output = 5
End Sub
Private Sub cmdCapture_Click()
Dim temp As Long
  hwdc = capCreateCaptureWindow("NeV0 Vision System", ws_child Or ws_visible, 0, 0, 640, 480, Picture1.hWnd, 0)
  If (hwdc <> 0) Then
    temp = SendMessage(hwdc, wm_cap_driver_connect, 0, 0)
    temp = SendMessage(hwdc, wm_cap_set_preview, 1, 0)
    temp = SendMessage(hwdc, WM_CAP_SET_PREVIEWRATE, 30, 0)
    startcap = True
    Else
    MsgBox ("No Webcam found")
  End If
End Sub
Private Sub cmdClose_Click()
Dim temp As Long
If startcap = True Then
temp = SendMessage(hwdc, WM_CAP_DRIVER_DISCONNECT, 0&, 0&)
startcap = False
End If
End Sub
Private Sub cmdVideoFormat_Click()
 Dim temp As Long
 If startcap = True Then
  temp = SendMessage(hwdc, WM_CAP_DLG_VIDEOFORMAT, 0&, 0&)
End If
End Sub

推荐答案

(sData， 1 ， 1 ))' 获得第一个字节 lLowByte = Asc(Mid

(sData, 1, 1)) ' get 1st byte lLowByte = Asc(Mid

(sData， 2 ， 1 ))' 获取第二个字节 lByte = JoinHighLow(lHighByte，lLowByte) Label1.Caption = CStr (lByte) DrawScale lByte 结束 如果 ' 每两字节的Fire Rx事件 MSComm1.RThreshold = 2 ' 输入数据时，一次输入2个字节 MSComm1.InputLen = 2 ' 2400波特，无奇偶校验，8个数据位，1个停止位 MSComm1.Settings = " ' 确保DTR线为低电平以防止图章重置 MSComm1.DTREnable = 错误 ' 使用COM9 MSComm1.CommPort = 1 ' 打开端口 MSComm1.PortOpen = 真实 结束 子 私有 功能 JoinHighLow(lHigh As 长，低 As 长) As 长 JoinHighLow =(lHigh *& H100)或 lLow 结束 功能 私有 子 DrawScale(lVal As 长) 图片1.Cls Picture1.Line( 0 ， 0 )-(lVal，Picture1.ScaleHeight)，vb3DShadow，BF 结束 子 私有 子 Command11_click() Dim PinNumber As Variant PinNumber = Text2.DataField MSComm1.Output = Chr

(sData, 2, 1)) ' Get 2nd byte lByte = JoinHighLow(lHighByte, lLowByte) Label1.Caption = CStr(lByte) DrawScale lByte End If ' Fire Rx Event Every Two Bytes MSComm1.RThreshold = 2 ' When Inputting Data, Input 2 Bytes at a time MSComm1.InputLen = 2 ' 2400 Baud, No Parity, 8 Data Bits, 1 Stop Bit MSComm1.Settings = "2400,N,8,1" ' Make sure DTR line is low to prevent Stamp reset MSComm1.DTREnable = False ' Use COM9 MSComm1.CommPort = 1 ' Open the port MSComm1.PortOpen = True End Sub Private Function JoinHighLow(lHigh As Long, lLow As Long) As Long JoinHighLow = (lHigh * &H100) Or lLow End Function Private Sub DrawScale(lVal As Long) Picture1.Cls Picture1.Line (0, 0)-(lVal, Picture1.ScaleHeight), vb3DShadow, BF End Sub Private Sub Command11_click() Dim PinNumber As Variant PinNumber = Text2.DataField MSComm1.Output = Chr

(PinNumber)' Chr

(PinNumber) 'Chr

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