[Mono-dev] Mono C# Serial Port problem

[buhochileno at gmail.com]

Alan_Chun wrote:
> HI, currently I am porting a windows app to linux using Mono. I have some
> difficulties to get the serial port work. here is the code(based on mono
> website):
>
>   
Hi Alan, cna you test this code in linux? (using of course /dev/ttyS0 or 
the correct serial device), I use lot of serial communications with mono 
inlinux and work ok, I don't know the current status of mono serialport 
in windows...also be sure to use kernel 2.6.24 or up in linux..

>  public static void Main(string[] args)
>     {
>         SerialPortTest myTest = new SerialPortTest();
>         myTest.Test();
>                
>     }
>
>     private SerialPort mySerial;
>
>     // Constructor
>     public SerialPortTest()
>     {
>     }
>
>     public void Test()
>     {
>         Console.WriteLine("Begin");
>         if (mySerial != null)
>             if (mySerial.IsOpen)
>                 mySerial.Close();
>
>         mySerial = new System.IO.Ports.SerialPort("COM3", 9600, Parity.Even,
> 7, StopBits.One);
>         mySerial.Open();
>         mySerial.DtrEnable = true;
>         mySerial.RtsEnable = true;
>         mySerial.Handshake = System.IO.Ports.Handshake.None;
>         mySerial.ReadTimeout = 400;
>         Thread t = new Thread(new ThreadStart(DataReceived));
>
>         t.Start();
>          string tmp = "5D.1";
>        
>          SendData(tmp);
>
>         // Should output some information about your modem firmware
>         //Console.WriteLine("Baaa");
>        // Console.WriteLine(ReadData());
>     }
>
>     public void DataReceived()
>     {
>         while (true)
>         {
>             byte tmpByte = 255;
>             string rxString = "";
>             //int tot = mySerial.BytesToRead;
>             tmpByte = (byte)mySerial.ReadByte();
>              
>             while (tmpByte != 255)
>             {
>                 rxString += ((char)tmpByte);
>                  mpByte = (byte)mySerial.ReadByte();
>             }
>               if (!string.IsNullOrEmpty(rxString))
>                   Console.WriteLine(rxString);
>         }
>         //return rxString;
>     }
>
> I ran this under windows using .netframwork run time, it is fine but under
> mono I always got this exception:
>
>
> Unhandled Exception: System.NullReferenceException: Object reference not set
> to an instance of an object
>   at (wrapper managed-to-native)
> System.IO.Ports.WinSerialStream:ClearCommError
> (int,System.IO.Ports.CommStat&)
>   at System.IO.Ports.WinSerialStream.get_BytesToRead () [0x00000]
>   at System.IO.Ports.SerialPort.get_BytesToRead () [0x00000]
>   at (wrapper remoting-invoke-with-check)
> System.IO.Ports.SerialPort:get_BytesToRead ()
>   at SerialPortTest.DataReceived () [0x00000]
>
>
>
>
> I have also tried BytesToRead, Read, ReadByte, all of them are working fine
> under windows using .net2.0 framwork. But once I use the mono runtime, the
> nightmare begins.
>
> Any help will be really apprecaited!
>
> Thanks  
>