串行端口system.unauthorizedaccess

Question

我的问题是，当我运行程序它工作得很好，但程序的一个周期后崩溃。下面是一些代码：

Private Sub Receiver(ByVal sender As Object, ByVal e As SerialDataReceivedEventArgs) Handles COMPort.DataReceived 
    Dim RXByte As Byte 
    key = 0 
    cut = False 
    c.Open() 
    Do 
     RXCnt = 0 
     Do 
      RXByte = COMPort.ReadByte 
      If (RXByte = 29) Then 
       c.Write(Chr(10)) 
       cut = True 
       c.Close() 
       If c.IsOpen = False Then 
         ts = "BLAH" 
         Process.Start(System.Windows.Forms.Application.StartupPath & "\e.exe", ts) 
         Process.Start(System.Windows.Forms.Application.StartupPath & "\Test.exe", c.PortName) 
       Else 

       End If 

      End If 
      If (cut = True) Then 
       Exit Do 
      End If 
      c.Write(Chr(RXByte)) 
      addText(Chr(RXByte)) 
      RXArray(RXCnt) = LookUpTable(RXByte >> 4) 
      RXCnt = RXCnt + 1 
      RXArray(RXCnt) = LookUpTable(RXByte And 15) 
      RXCnt = RXCnt + 1 
      RXArray(RXCnt) = " " 
      RXCnt = RXCnt + 1 
      SpaceCount = (SpaceCount + 1) And 31  
      If SpaceCount = 0 Then      
       RXArray(RXCnt) = Chr(13) ' CR 
       RXCnt = RXCnt + 1 
       RXArray(RXCnt) = Chr(10) ' LF 
       RXCnt = RXCnt + 1 
      Else 
       If (SpaceCount And 3) = 0 Then   
        RXArray(RXCnt) = " " 
        RXCnt = RXCnt + 1 
        RXArray(RXCnt) = " " 
        RXCnt = RXCnt + 1 
       End If 
      End If 
     Loop Until (COMPort.BytesToRead = 0) 
     Me.Invoke(New MethodInvoker(AddressOf Display)) 
    Loop Until (COMPort.BytesToRead = 0) 
    c.Close() 
End Sub 

我相信这个问题在代码

Process.Start(System.Windows.Forms.Application.StartupPath & "\Test.exe", c.PortName) 

系统抛出一个System.UnauthorizedAccessException的错误在这一点上发生。此外，测试程序还与相同的串行端口进行通信。当我运行程序时，进程启动并完成，但当前进程抛出错误。这是UAC错误吗？

Answer 1

两个程序不能同时打开串口。在这些情况下尝试打开串口会引发该异常：

访问被拒绝给端口。

- 或 -

当前过程，或在系统上的另一过程，已经有指定的COM端口或者由的SerialPort实例或在非托管代码中打开。

Source。所以你不能在你的程序中打开串口，也可以在test.exe。