I found this code some time ago, and is working very well, I don't remember
the author but I have made some changes, I hope it helps
meke an instance:
private MPSSA.CommPort myCPort = new MPSSA.CommPort();
..
..
..
set the properties:
myCPort.PortNum = Convert.ToInt32(dsEmpresa1.Empresa.Rows[0]["ComPort"]);
myCPort.BaudRate = Convert.ToInt32(dsEmpresa1.Empresa.Rows[0]["BaudRate"]);
myCPort.ByteSize = Convert.ToByte(dsEmpresa1.Empresa.Rows[0]["ByteSize"]);
myCPort.Parity = Convert.ToByte(dsEmpresa1.Empresa.Rows[0]["Parity"]);
myCPort.StopBits = Convert.ToByte(dsEmpresa1.Empresa.Rows[0]["StopBit"]);
myCPort.ReadTimeout =
Convert.ToInt32(dsEmpresa1.Empresa.Rows[0]["ReadTimeOut"]);
..
..
..
use open method
myPort.Open();
..
..
..
a simple read:
byte[] ba = {0x00};
ba = myPort.Read(1);
..
..
..
and here is the class:
using System;
using System.Runtime.InteropServices;
namespace MPSSA
{
public class CommPort
{
public int PortNum;
public int BaudRate;
public byte ByteSize;
public byte Parity; // 0-4=no,odd,even,mark,space
public byte StopBits; // 0,1,2 = 1, 1.5, 2
public int ReadTimeout;
//comm port win32 file handle
private int hComm = -1;
public bool Opened = false;
//win32 api constants
private const uint GENERIC_READ = 0x80000000;
private const uint GENERIC_WRITE = 0x40000000;
private const int OPEN_EXISTING = 3;
private const int INVALID_HANDLE_VALUE = -1;
[StructLayout(LayoutKind.Sequential)]
public struct DCB
{
//taken from c struct in platform sdk
public int DCBlength; // sizeof(DCB)
public int BaudRate; // current baud rate
/* these are the c struct bit fields, bit twiddle flag to set
public int fBinary; // binary mode, no EOF check
public int fParity; // enable parity checking
public int fOutxCtsFlow; // CTS output flow control
public int fOutxDsrFlow; // DSR output flow control
public int fDtrControl; // DTR flow control type
public int fDsrSensitivity; // DSR sensitivity
public int fTXContinueOnXoff; // XOFF continues Tx
public int fOutX; // XON/XOFF out flow control
public int fInX; // XON/XOFF in flow control
public int fErrorChar; // enable error replacement
public int fNull; // enable null stripping
public int fRtsControl; // RTS flow control
public int fAbortOnError; // abort on error
public int fDummy2; // reserved
*/
public uint flags;
public ushort wReserved; // not currently used
public ushort XonLim; // transmit XON threshold
public ushort XoffLim; // transmit XOFF threshold
public byte ByteSize; // number of bits/byte, 4-8
public byte Parity; // 0-4=no,odd,even,mark,space
public byte StopBits; // 0,1,2 = 1, 1.5, 2
public char XonChar; // Tx and Rx XON character
public char XoffChar; // Tx and Rx XOFF character
public char ErrorChar; // error replacement character
public char EofChar; // end of input character
public char EvtChar; // received event character
public ushort wReserved1; // reserved; do not use
}
[StructLayout(LayoutKind.Sequential)]
private struct COMMTIMEOUTS {
public int ReadIntervalTimeout;
public int ReadTotalTimeoutMultiplier;
public int ReadTotalTimeoutConstant;
public int WriteTotalTimeoutMultiplier;
public int WriteTotalTimeoutConstant;
}
[StructLayout(LayoutKind.Sequential)]
private struct OVERLAPPED {
public int Internal;
public int InternalHigh;
public int Offset;
public int OffsetHigh;
public int hEvent;
}
[DllImport("kernel32.dll")]
private static extern int CreateFile(
string lpFileName, // file name
uint dwDesiredAccess, // access mode
int dwShareMode, // share mode
int lpSecurityAttributes, // SD
int dwCreationDisposition, // how to create
int dwFlagsAndAttributes, // file attributes
int hTemplateFile // handle to template file
);
[DllImport("kernel32.dll")]
private static extern bool GetCommState(
int hFile, // handle to communications device
ref DCB lpDCB // device-control block
);
[DllImport("kernel32.dll")]
private static extern bool BuildCommDCB(
string lpDef, // device-control string
ref DCB lpDCB // device-control block
);
[DllImport("kernel32.dll")]
private static extern bool SetCommState(
int hFile, // handle to communications device
ref DCB lpDCB // device-control block
);
[DllImport("kernel32.dll")]
private static extern bool GetCommTimeouts(
int hFile, // handle to comm device
ref COMMTIMEOUTS lpCommTimeouts // time-out values
);
[DllImport("kernel32.dll")]
private static extern bool SetCommTimeouts(
int hFile, // handle to comm device
ref COMMTIMEOUTS lpCommTimeouts // time-out values
);
[DllImport("kernel32.dll")]
private static extern bool ReadFile(
int hFile, // handle to file
byte[] lpBuffer, // data buffer
int nNumberOfBytesToRead, // number of bytes to read
ref int lpNumberOfBytesRead, // number of bytes read
ref OVERLAPPED lpOverlapped // overlapped buffer
);
[DllImport("kernel32.dll")]
private static extern bool WriteFile(
int hFile, // handle to file
byte[] lpBuffer, // data buffer
int nNumberOfBytesToWrite, // number of bytes to write
ref int lpNumberOfBytesWritten, // number of bytes written
ref OVERLAPPED lpOverlapped // overlapped buffer
);
[DllImport("kernel32.dll")]
private static extern bool CloseHandle(int hObject);
// handle to object
[DllImport("kernel32.dll")]
private static extern uint GetLastError();
public void Open()
{
DCB dcbCommPort = new DCB();
COMMTIMEOUTS ctoCommPort = new COMMTIMEOUTS();
// OPEN THE COMM PORT.
hComm = CreateFile("COM" + PortNum ,GENERIC_READ | GENERIC_WRITE,0,
0,OPEN_EXISTING,0,0);
// IF THE PORT CANNOT BE OPENED, BAIL OUT.
if(hComm == INVALID_HANDLE_VALUE)
{
throw(new ApplicationException("Comm Port Can Not Be Opened"));
}
// SET THE COMM TIMEOUTS.
GetCommTimeouts(hComm,ref ctoCommPort);
ctoCommPort.ReadTotalTimeoutConstant = ReadTimeout;
ctoCommPort.ReadTotalTimeoutMultiplier = 0;
ctoCommPort.WriteTotalTimeoutMultiplier = 0;
ctoCommPort.WriteTotalTimeoutConstant = 0;
SetCommTimeouts(hComm,ref ctoCommPort);
// SET BAUD RATE, PARITY, WORD SIZE, AND STOP BITS.
GetCommState(hComm, ref dcbCommPort);
dcbCommPort.BaudRate=BaudRate;
dcbCommPort.flags=0;
//dcb.fBinary=1;
dcbCommPort.flags|=1;
if (Parity>0)
{
//dcb.fParity=1
dcbCommPort.flags|=2;
}
dcbCommPort.Parity = Parity;
dcbCommPort.ByteSize = ByteSize;
dcbCommPort.StopBits = StopBits;
if (!SetCommState(hComm, ref dcbCommPort))
{
//uint ErrorNum=GetLastError();
throw(new ApplicationException("Comm Port Can Not Be Opened"));
}
//unremark to see if setting took correctly
//DCB dcbCommPort2 = new DCB();
//GetCommState(hComm, ref dcbCommPort2);
Opened = true;
}
public void Close()
{
if (hComm!=INVALID_HANDLE_VALUE) {
CloseHandle(hComm);
}
Opened = false;
}
public byte[] Read(int NumBytes)
{
byte[] BufBytes;
byte[] OutBytes;
BufBytes = new byte[NumBytes];
if (hComm!=INVALID_HANDLE_VALUE)
{
OVERLAPPED ovlCommPort = new OVERLAPPED();
int BytesRead=0;
ReadFile(hComm,BufBytes,NumBytes,ref BytesRead,ref ovlCommPort);
OutBytes = new byte[BytesRead];
Array.Copy(BufBytes,OutBytes,BytesRead);
}
else
{
throw(new ApplicationException("Comm Port Not Open"));
}
return OutBytes;
}
public void Write(byte[] WriteBytes)
{
if (hComm!=INVALID_HANDLE_VALUE)
{
OVERLAPPED ovlCommPort = new OVERLAPPED();
int BytesWritten = 0;
WriteFile(hComm,WriteBytes,WriteBytes.Length,ref BytesWritten,ref
ovlCommPort);
}
else
{
throw(new ApplicationException("Comm Port Not Open"));
}
}
}
class HexCon
{
//converter hex string to byte and byte to hex string
public static string ByteToString(byte[] InBytes)
{
string StringOut="";
foreach (byte InByte in InBytes)
{
StringOut=StringOut + String.Format("{0:X2} ",InByte);
}
return StringOut;
}
public static byte[] StringToByte(string InString)
{
string[] ByteStrings;
ByteStrings = InString.Split(" ".ToCharArray());
byte[] ByteOut;
ByteOut = new byte[ByteStrings.Length-1];
for (int i = 0;i==ByteStrings.Length-1;i++)
{
ByteOut = Convert.ToByte(("0x" + ByteStrings));
}
return ByteOut;
}
}
}
