bug in serialport.close() ?

bug in serialport.close() ?

• videogamer2791

  OK, it is not DiscardOutBuffer(). The documentation for the Close() method specifically warns that we should "wait for some amount of time" before opening the port again. The SerialPort class no doubt needs some time for threads to exit.
  
  Well, let's punt and avoid opening and closing the port over and over again. Call Open() when you initialize the port and Close() when your program exits. This is the normal use for a SerialPort object and might avoid some obscure deadlock inside the class.
  
  If you want a better answer, you'll need to tell us what exceptions are being raised...
  
  
  
  

• DMET System

  I have the same issue. I have a pocket pc application that uses the IR port in raw mode using the serialport component from .net. It works most of the time but sometimes the port stops working
  At the beginning i opened the port when opening the windows form and closed the port when leaving the form but then i tried to open and close the port after getting time outs on the comunication with a custom device and it seems to improve somehow the stablility of the code. However, now it hangs sometimes on the close call as described in the previous posts
  No exceptions are thrown and when stoping the process in the debugger it is at the close call.
  
  what is the correct sequence to flush and reset the port
  
  

• ChristosX

  I thought it wa something like that too but i tried everything ans the problem's stil there. First, i thought it was due to multitasking problems but then i noticed i had the problem only with a single loop. Here is the code.
  
  while(true)
  {
  read_FDP();
  }
  
  public Int16 read_FDP(byte adresse)
  {
  try { Close(); }
  catch { };
  
  if (!IsOpen) //If port closed
  {
  
  try { Open(); }
  catch (Exception) { }
  
  //If port is opened
  if (IsOpen)
  {
  DiscardInBuffer(); //discard the buffer
  
  try { Write(SOF_string); } //start of frame
  catch(Exception){return (-1);}
  
  trame_out[0] = 13; //command type
  trame_out[1] = adresse; //adress
  
  try{Write(trame_out, 0, 2);}
  catch(Exception){ return (-1);}
  
  try { Write("!"); } //end of frame
  catch (Exception) { return 1; }
  
  //on verifie si ca a fonctionne
  try { Read(trame_in, 0, 3); } // Waiting for 3 chars
  catch (Exception)
  {
  DiscardInBuffer();
  DiscardOutBuffer();
  
  try { Close(); }
  catch { }; //Close the port
  return (-1); //no response
  }
  try { Close(); }                         edit :                //GENERALLY THIS ONE IS THE PROBLEM
  catch { }; //Close the port
  
  if (trame_in[0] == '!' && trame_in[1] == 13)
  {
  return trame_in[2]; // Return the read data
  }
  else
  return (-3);
  }
  }
  return (-2);
  }
  
  Impossible to make it loop more than a few minutes.
  
  Does anyone have a suggestion
  
  Thanks for your help !
  
  @@@
  
  
  

• benoit texier

  The same problem, waiting solution...
  

• Martin Thorsen

  I have the same issue. I have a pocket pc application that uses the IR port in raw mode using the serialport component from .net. It works most of the time but sometimes the port stops working
  At the beginning i opened the port when opening the windows form and closed the port when leaving the form but then i tried to open and close the port after getting time outs on the comunication with a custom device and it seems to improve somehow the stablility of the code. However, now it hangs sometimes on the close call as described in the previous posts
  No exceptions are thrown and when stoping the process in the debugger it is at the close call.
  
  what is the correct sequence to flush and reset the port
  

• armand

  are we the only ones to have that problem and not the solution
  
  Does anyone have others suggestions
  
  Thanks a lot ;-)
  
  
  
  
  

• Keith R. Smith

  I edited the sample code...
  
  Thanks !!
  
  
  

• Twosheds

  Yes i saw that in the docs. Another person told me the same. I will have to change my code.
  
  Thanks for your help ! I'll give some results later...
  
  Thanks again !!!
  
  
  
  
  

• Wayne Erfling

  Everything works...
  
  Thanks a lot.
  
  
  

• Indinfer

  This is probably caused by the serial port still having bytes to send and the device has turned off the handshake. Check the BytesToWrite property value. Use DiscardOutBuffer() to throw away any unsent characters.
  
  
  
  

• L_O_L

  A bunch of Close() calls, which one does it hang on You are also silently discarding exceptions, at least use Debug.Print to know what is going wrong. Also show us the code that initializes the SerialPort instance.
  
  
  
  

• ControlBox

  Yes you're right for the exceptions but this soft is only for a demonstration. I normally don't need them.
  
  I will make some tries with printing.
  
  I initialize the serialport just with that :
  
  BaudRate = 921600; //Not a problem it uses a cdc driver
  ReadTimeout = 300;
  WriteTimeout = 300;
  
  Thanks for your help
  
  
  
  
  
  

• Tmoeller

  Which Close() does it hang on
  
  
  
  

• Harald xyz

  I have moved this thread here from Windows Forms forum. Hopefully you'll get a response from your question.
  
  Regards,
  
  -chris
  
  
• bug in serialport.close() ?