private void Init()
{
// create a system event for synchronizing Closing
closeEvent = CommAPI.CreateEvent(true, false, closeEventName);
rxBuffer = new byte[rxBufferSize + 1000];
txBuffer = new byte[txBufferSize];
portSettings = new DetailedPortSettings();
}
public bool Close()
{
if (!isOpen)
{
return(false);
}
if (CommAPI.CloseHandle(hPort))
{
CommAPI.SetEvent(closeEvent);
isOpen = false;
hPort = (IntPtr)CommAPI.INVALID_HANDLE_VALUE;
CommAPI.SetEvent(closeEvent);
return(true);
}
return(false);
}
private void CommEventThread()
{
CommEventFlags eventFlags = new CommEventFlags();
byte[] readbuffer = new byte[1000];
int bytesread = 0;
// specify the set of events to be monitored for the port.
CommAPI.SetCommMask(hPort, CommEventFlags.RXCHAR);
try {
// let Open() know we're started
threadStarted.Set();
while (hPort != (IntPtr)CommAPI.INVALID_HANDLE_VALUE)
{
try {
// wait for a Comm event
if (!CommAPI.WaitCommEvent(hPort, ref eventFlags))
{
int e = Marshal.GetLastWin32Error();
if (e == (int)APIErrors.ERROR_IO_PENDING)
{
// IO pending so just wait and try again
Thread.Sleep(0);
continue;
}
if (e == (int)APIErrors.ERROR_INVALID_HANDLE)
{
// Calling Port.Close() causes hPort to become invalid
// Since Thread.Abort() is unsupported in the CF, we must
// accept that calling Close will throw an error here.
// Close signals the closeEvent, so wait on it
// We wait 1 second, though Close should happen much sooner
int eventResult = CommAPI.WaitForSingleObject(closeEvent, 1000);
if (eventResult == (int)APIConstants.WAIT_OBJECT_0)
{
// the event was set so close was called
hPort = (IntPtr)CommAPI.INVALID_HANDLE_VALUE;
// reset our ResetEvent for the next call to Open
threadStarted.Reset();
return;
}
}
// WaitCommEvent failed!
string error = String.Format("Wait Failed: {0}", e);
throw new CommPortException(error);
}
}
catch (Exception e) {
throw e;
}
try {
// Re-specify the set of events to be monitored for the port.
CommAPI.SetCommMask(hPort, CommEventFlags.RXCHAR);
}
catch (Exception e) {
throw e;
}
// check for RXCHAR
if ((eventFlags & CommEventFlags.RXCHAR) != 0)
{
if (DataReceived != null)
{
try {
// data came in, put it in the buffer and set the event
CommAPI.ReadFile(hPort, readbuffer, 1000, ref bytesread);
}
catch (Exception e) {
throw e;
}
if (bytesread >= 1)
{
rxBufferBusy.WaitOne();
try {
// store the byte in out buffer and increment the pointer
Array.Copy(readbuffer, 0, rxBuffer, (int)prxBuffer, (int)bytesread);
prxBuffer += (uint)bytesread;
}
catch (Exception e) {
throw e;
}
finally {
rxBufferBusy.ReleaseMutex();
} {
// prxBuffer gets reset when the Input value is read. (FIFO)
if (DataReceived != null)
{
DataReceived();
}
}
}
}
}
} // while(true)
} // try
catch (Exception e) {
throw e;
}
}
public bool Open()
{
if (isOpen)
{
return(false);
}
hPort = CommAPI.CreateFile(portName);
if (hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE)
{
int e = Marshal.GetLastWin32Error();
if (e == (int)APIErrors.ERROR_ACCESS_DENIED)
{
// port is unavailable
return(false);
}
if (e == (int)APIErrors.ERROR_PORT_UNAVAIL)
{
// port is unavailable
return(false);
}
// ClearCommError failed!
string error = String.Format("CreateFile Failed: {0}", e);
throw new CommPortException(error);
}
isOpen = true;
// set queue sizes
CommAPI.SetupComm(hPort, rxBufferSize, txBufferSize);
// transfer the port settings to a DCB structure
dcb.BaudRate = (uint)portSettings.BasicSettings.BaudRate;
dcb.ByteSize = portSettings.BasicSettings.ByteSize;
dcb.EofChar = (sbyte)portSettings.EOFChar;
dcb.ErrorChar = (sbyte)portSettings.ErrorChar;
dcb.EvtChar = (sbyte)portSettings.EVTChar;
dcb.fAbortOnError = portSettings.AbortOnError;
dcb.fBinary = true;
dcb.fDsrSensitivity = portSettings.DSRSensitive;
dcb.fDtrControl = (DCB.DtrControlFlags)portSettings.DTRControl;
dcb.fErrorChar = portSettings.ReplaceErrorChar;
dcb.fInX = portSettings.InX;
dcb.fNull = portSettings.DiscardNulls;
dcb.fOutX = portSettings.OutX;
dcb.fOutxCtsFlow = portSettings.OutCTS;
dcb.fOutxDsrFlow = portSettings.OutDSR;
dcb.fParity = (portSettings.BasicSettings.Parity == Parity.none) ? false : true;
dcb.fRtsControl = (DCB.RtsControlFlags)portSettings.RTSControl;
dcb.fTXContinueOnXoff = portSettings.TxContinueOnXOff;
dcb.Parity = (byte)portSettings.BasicSettings.Parity;
dcb.StopBits = (byte)portSettings.BasicSettings.StopBits;
dcb.XoffChar = (sbyte)portSettings.XoffChar;
dcb.XonChar = (sbyte)portSettings.XonChar;
dcb.XonLim = dcb.XoffLim = (ushort)(rxBufferSize / 10);
CommAPI.SetCommState(hPort, dcb);
// store some state values
brk = 0;
dtr = dcb.fDtrControl == DCB.DtrControlFlags.Enable ? 1 : 0;
rts = dcb.fRtsControl == DCB.RtsControlFlags.Enable ? 1 : 0;
// set the Comm timeouts
CommTimeouts ct = new CommTimeouts();
// reading we'll return immediately
// this doesn't seem to work as documented
ct.ReadIntervalTimeout = uint.MaxValue; // this = 0xffffffff
// ct.ReadIntervalTimeout = 2;
ct.ReadTotalTimeoutConstant = 2;
ct.ReadTotalTimeoutMultiplier = uint.MaxValue;
// writing we'll give 5 seconds
ct.WriteTotalTimeoutConstant = 5;
ct.WriteTotalTimeoutMultiplier = 0;
CommAPI.SetCommTimeouts(hPort, ct);
// start the receive thread
eventThread = new Thread(new ThreadStart(CommEventThread));
eventThread.Priority = ThreadPriority.AboveNormal;
eventThread.Start();
// wait for the thread to actually get spun up
threadStarted.WaitOne();
return(true);
}
