xtern 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);
}
}
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"));
}
}
}

}
}

由于篇幅，以及串口通信涉及内容广泛，我在这里只讲这些。