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  1. 我正在尝试通过 mscomm 端口发送和接收数据，但接收到的数据类型不匹配。所以我应该怎么做才能避免这个错误，我需要将数据作为整数发送并尽可能将其作为字符串接收，至少我应该将它作为整数数据类型。以下是我的代码，请帮我解决这个问题。

  2. 发送和接收代码在独立运行时工作。

Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

Private Sub Command1_Click()
    If (MSComm1.PortOpen = False) Then
        MSComm1.PortOpen = True
    End If
    Command1.Enabled = False
    Command2.Enabled = True
    Text3.Text = "COM1, Baud - 9600, Databit - 8, Parity - None, Stopbit - 1....CONNECTED." & Text3.Text
End Sub

Private Sub Command2_Click()
    If (MSComm1.PortOpen = True) Then
        MSComm1.PortOpen = False
    End If
    Command1.Enabled = True
    Command2.Enabled = False
    Text3.Text = "DISCONNECTED" & Text3.Text
End Sub

Private Sub Command3_Click()
    Text1.Text = " "
    Text2.Text = " "
    Text3.Text = "CLEARED" & Text3.Text
End Sub

Private Sub Command4_Click()    
    MSComm1.Output = Text2.Text
    Text3.Text = "SENDING" & Text3.Text
End Sub

Private Sub Command5_Click()
    Text3.Text = " "
End Sub

Private Sub Form_Load()
    MSComm1.CommPort = 1
    MSComm1.Settings = "9600,N,8,1"
    MSComm1.DTREnable = True
    MSComm1.Handshaking = comRTS
    MSComm1.InBufferSize = 2
    MSComm1.RThreshold = MSComm1.InBufferSize
    MSComm1.RTSEnable = True
    MSComm1.InputLen = 2
    MSComm1.InputMode = comInputModeText
    MSComm1.NullDiscard = True
    MSComm1.OutBufferSize = 2
    MSComm1.SThreshold = MSComm1.OutBufferSize    
    MSComm1.PortOpen = True  
End Sub

Private Sub Form_Unload(Cancel As Integer)
    If (MSComm1.PortOpen = True) Then
        MSComm1.PortOpen = False
    End If
End Sub

Private Sub MSComm1_OnComm()
    Dim Buffer As String
    Select Case MSComm1.CommEvent
        Case comEvReceive
            'Text1.Text = " "
            Buffer = Cstr(MSComm1.Input)
            Text1.Text = Buffer
    End Select
End Sub
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1 回答 1

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我认为主要问题是您在没有任何传输控制尝试的情况下异步发送数据。由于要传输多个字符，因此您需要告诉接收器新传输的开始位置，以使其找到正确的偏移量。

在您的情况下，您说您只想发送 0..100 范围内的值。通过使用 0 到 255 范围内的单个字节值，可以寻址，因此在这种情况下，每个值发送一个字节就足够了，对于单个字符，不需要传输控制。

这是一个将数字转换为单个字节、发送并重新转换为数字的示例：

Option Explicit
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

Private Sub cmdOpen_Click()
    If (MSComm1.PortOpen = False) Then
        MSComm1.PortOpen = True
    End If
    cmdOpen.Enabled = False
    cmdClose.Enabled = True
    txtState.Text = "COM1, Baud - 9600, Databit - 8, Parity - None, Stopbit - 1....CONNECTED." & txtState.Text
End Sub

Private Sub cmdClose_Click()
    If (MSComm1.PortOpen = True) Then
        MSComm1.PortOpen = False
    End If
    cmdOpen.Enabled = True
    cmdClose.Enabled = False
    txtState.Text = "DISCONNECTED" & txtState.Text
End Sub

Private Sub cmdClear_Click()
    txtReceived.Text = " "
    txtSend.Text = " "
    txtState.Text = "CLEARED" & txtState.Text
End Sub

Private Sub cmdSend_Click()
Dim Number As Byte
    'some checking - needed depending on source of data
    If Not IsNumeric(txtSend.Text) Then
        MsgBox "only numbers (from 0 to 255)"
        Exit Sub
    End If
    If Val(txtSend.Text) < 0 Or Val(txtSend.Text) > 255 Then
        MsgBox "out of range (from 0 to 255)"
        Exit Sub
    End If

    Number = CByte(Val(txtSend.Text))
    MSComm1.Output = Chr(Number)
    txtState.Text = "SENDING" & txtState.Text
End Sub

Private Sub cmdClearState_Click()
    txtState.Text = " "
End Sub

Private Sub Form_Load()
    MSComm1.CommPort = 1
    MSComm1.Settings = "9600,N,8,1"
    MSComm1.DTREnable = True
    MSComm1.Handshaking = comNone 'comRTS i only got a 3-wire connection - so no handshaking
    MSComm1.InBufferSize = 1024 'not 2 we don't want a buffer overflow THAT fast
    MSComm1.RThreshold = 1 'Raise OnComm-Event if 1 character is in Rx-buffer
    MSComm1.RTSEnable = True
    MSComm1.InputLen = 1 'get one character at a time
    MSComm1.InputMode = comInputModeText 'the Binary mode never worked out for me - even when transmitting binary data
    MSComm1.NullDiscard = False 'also NULL-Characters will be received
    MSComm1.OutBufferSize = 512 'again we don't want overflow
    MSComm1.SThreshold = 0 'don't hold back data - blow them out directly
    MSComm1.PortOpen = True
End Sub

Private Sub Form_Unload(Cancel As Integer)
    If (MSComm1.PortOpen = True) Then
        MSComm1.PortOpen = False
    End If
End Sub

Private Sub MSComm1_OnComm()
    Dim Buffer As String
    Select Case MSComm1.CommEvent
        Case comEvReceive
            'txtReceived.Text = " "
            Buffer = MSComm1.Input
            txtReceived.Text = Asc(Buffer)
            txtState.Text = "RX" + txtState.Text
    End Select
End Sub
于 2013-06-10T16:51:45.290 回答