关于mscomm的通信有关问题

关于mscomm的通信问题
先看代码： 
Option Explicit 

Private Sub CmdClear_Click() 
TxtSend.Text = "" 
TxtReceive.Text = "" 
End Sub 
Private Sub CmdExit_Click() 
Comm1.PortOpen = False 
End 
End Sub 

Private Sub Comm1_OnComm() 
Select Case Comm1.CommEvent 
  Case comEvCD 
  Case comEvCTS 
  Case comEvDSR 
  Case comEvRing 
  Case comEvReceive 
  Dim t&, buf$, StrPro% 
  t = GetTickCount() 
  Do 
  DoEvents 
  Loop Until GetTickCount - t > 100 
  buf = Trim(Comm1.Input) 
  If Len(buf) < 2 Then Exit Sub 
  TxtReceive.Text = buf 
  StrPro = InStr(1, buf, "%%") 
  If StrPro < 1 Then 
  buf = 0 
  Comm1.Output = "未接受到正确的格式" 
  Else 
  'TxtReceive.Text = Left(buf, Len(buf) - 2) 
  Comm1.Output = "执行" & Right(buf, Len(buf) - (StrPro + 1)) & "命令成功..." 
  End If 
  Case comEvSend 
  End Select 
End Sub 

Private Sub Form_Load() 
Comm1.PortOpen = True 
Comm1.InBufferCount = 0 
Comm1.OutBufferCount = 0 
End Sub 
Private Sub TxtSend_KeyPress(KeyAscii As Integer) 
If KeyAscii = 13 Then 
  Comm1.Output = Trim(TxtSend.Text) 
End If 
End Sub 
各位老师 
  我想当输入格式错误时文本框中显示“格式不正确”，但输入格式正确时显示“格式正确”，但是我不想用如下语句 
TxtReceive.text="格式正确" 
我想用Comm1.Output = "执行格式正确"这条指令执行后显示出“格式正确” 
为啥上面的程序不能实现呢， 
不知道哪里出现了问题。 
请教各位老师 
如果可以的话请留下QQ号码，以供经常交流。 
先行谢过。

[解决办法]

VB code

Private Sub Comm1_OnComm()    Select Case Comm1.CommEvent        Case 2            sum = sum + 1            Text2 = sum            Dim t&, buf$, StrPro%            t = GetTickCount()            Do                DoEvents            Loop Until GetTickCount - t > 100            buf = Comm1.Input            If Len(buf) < 2 Then Exit Sub            TxtReceive.Text = buf            StrPro = InStr(1, buf, "%%")            If StrPro < 1 Then                buf = 0                Comm1.Output = "未接受到正确的格式"            Else                Comm1.Output = "执行" & Right(buf, Len(buf) - (StrPro + 1)) & "命令成功..."            End If    End SelectEnd SubPrivate Sub Form_Load()    Comm1.Settings = "9600,n,8,1"    Comm1.PortOpen = True    Comm1.RThreshold = 1    Comm1.InBufferCount = 0    Comm1.OutBufferCount = 0    Comm1.InputLen = 0    Comm1.InputMode = comInputModeTextEnd Sub