Option Explicit
Dim indata As String
Private Sub Command1_Click()
  Dim aa(46) As Byte
  aa(0) = &H55
  aa(1) = &H55
  aa(2) = &HF0
  aa(3) = &H29
  aa(4) = &HE7
  aa(5) = &H4C
  aa(6) = &H61
  aa(7) = &H63
  aa(8) = &H6B
  aa(9) = &H20
  aa(10) = &H6F
  aa(11) = &H66
  aa(12) = &H20
  aa(13) = &H5A
  aa(14) = &H65
  aa(15) = &H72
  aa(16) = &H6F
  aa(17) = &HA
  aa(18) = &H52
  aa(19) = &H65
  aa(20) = &H70
  aa(21) = &H6F
  aa(22) = &H72
  aa(23) = &H74
  aa(24) = &H20
  aa(25) = &H54
  aa(26) = &H69
  aa(27) = &H6D
  aa(28) = &H65
  aa(29) = &H3A
  aa(30) = &HA
  aa(31) = &H30
  aa(32) = &H34
  aa(33) = &H2F
  aa(34) = &H31
  aa(35) = &H32
  aa(36) = &H20
  aa(37) = &H20
  aa(38) = &H31
  aa(39) = &H34
  aa(40) = &H3A
  aa(41) = &H30
  aa(42) = &H32
  aa(43) = &HF0
  aa(44) = &HD
  aa(45) = &H55
  aa(46) = &H55
  Text1.Text = ""
  Text2.Text = ""
  indata = ""
  MSComm1.InBufferCount = 0
  MSComm1.OutBufferCount = 0
  MSComm1.Output = aa   '发送数据
End Sub

Private Sub Form_Load()
   = 3
  MSComm1.Settings = "9600,N,8,1"
  MSComm1.InBufferSize = 1024
  MSComm1.OutBufferSize = 4096
  MSComm1.InBufferCount = 0
  MSComm1.OutBufferCount = 0
  MSComm1.SThreshold = 1
  MSComm1.RThreshold = 1
  MSComm1.InputMode = 1
  MSComm1.InputLen = 0
  MSComm1.PortOpen = True
  Text2.Text = ""
  indata = ""
End Sub

Private Sub MSComm1_OnComm()
Dim InByte() As Byte
Dim i As Integer
  Select Case
     Case comEvReceive
       InByte = MSComm1.Input      '读取数据
       For i = LBound(InByte) To UBound(InByte)
           If Len(Hex(InByte(i))) = 1 Then
              indata = indata & "0" & Hex(InByte(i)) & Chr(32)
           Else
              indata = indata + Hex(InByte(i)) + Chr(32)
           End If
       Next i
     Text1.Text = Trim(indata)
     Text4.Text = Mid(Trim(indata), 18, Len(indata) - 27)   '问题代码行
  End Select
End Sub

想请教下Mid(Trim(indata), 18, Len(indata) - 27)这段代码为何报错（报错内容为：实时错误‘5’，无效的过程调用或参数），我是做单机发送及接收数据的，根据显示变量indata当作的长度为140，也就是a（）数组当中的数据，为什么把Len(indata) - 27这段改成"数值"就可以，而用表达式就不行

[此贴子已经被作者于2016-12-29 14:36编辑过]

根据您说的那样去弄，还是出现同样的问题：实时错误‘5’，无效的过程调用或参数

这个问题已解决，由于是串口异步问题造成的，谢谢！