读取串口内容并判断是否重复

zybiz

各位大神，我VBA小白，参考网上资料，做了一个从串口读取内容，记录下时间和内容的代码，但是还需要每读取一次内容和之前的比较是否有重复，重复则提示内容重复，否则才记录下来，不知怎么做，请大家帮忙，谢谢！
代码如下：
Private Sub CommandButton1_Click()
MkDir ThisWorkbook.Path & "\" & Format(Now(), "yyyymmddhhmm")
ThisWorkbook.SaveAs ThisWorkbook.Path & "\" & Format(Now(), "yyyymmddhhmm") & "\" & Format(Now(), "yyyymmddhhmm") & ".xls"
Application.Quit
End Sub

Private Sub Label1_Click()

End Sub

Private Sub Label2_Click()

End Sub

Private Sub MSComm1_OnComm()
Dim t1 As Long, com_String As String
Static i As Integer
t1 = Timer

Select Case MSComm1.CommEvent
  Case comEvReceive
       MSComm1.RThreshold = 0
  Do
    DoEvents
  Loop While Timer - t1 < 0.05
  com_String = MSComm1.Input
  MSComm1.RThreshold = 1
  i = i + 1: If i > 10 Then i = 1
  Application.Cells(i + 1, "B").Value = com_String
  Cells(i + 1, "A") = Format(Now(), "yyyy-mm-dd,hh:mm:ss")
  Me.Label3.Caption = i
  If i = 10 Then
  MkDir ThisWorkbook.Path & "\" & Format(Now(), "yyyymmddhhmm")
  ThisWorkbook.SaveAs ThisWorkbook.Path & "\" & Format(Now(), "yyyymmddhhmm") & "\" & Format(Now(), "yyyymmddhhmm") & ".xls"
  Range("a2:a30").Clear
  Range("b2:b30").Clear
  End If
  End Select

End Sub
Private Sub iniMscomm()
'On Error Resume Next
MSComm1.CommPort = 15
MSComm1.Settings = "38400,N,8,1"
MSComm1.PortOpen = True
MSComm1.RThreshold = 1
MSComm1.InputLen = 0
MSComm1.InputMode = comInputModeText
MSComm1.RTSEnable = True
MSComm1.InBufferCount = 0
End Sub
Private Sub UserForm_initialize()
iniMscomm
  ActiveSheet.Cells.Clear
  Cells(1, "A") = Format("时间")
  Cells(1, "B") = Format("记录")
  Me.Label1.Caption = ("请开始扫描!")
  Me.Label1.FontSize = 50
  Me.Label2.Caption = ("记录数量:")
  Me.Label2.FontSize = 20
  Me.Label3.Caption = ("0")
  Me.Label3.FontSize = 20
  Me.Label3.ForeColor = &HC000&
  Me.CommandButton1.Caption = ("退出保存")
  Me.CommandButton1.FontSize = 20
End Sub