用CreateFile打开端口后，怎么关闭端口？

Question

曾经收集的一个类,给你看看!
using System;
using System.Runtime.InteropServices;namespace JustinIO 
{   
/// <summary>
/// 这是一个关于调用串口的类
/// </summary>
public class CommPort 
{ public int PortNum=1; 
public int BaudRate=9600;
public byte ByteSize=8;
public byte Parity=0; // 0-4=no,odd,even,,space 
public byte StopBits=0; // 0,1,2 = 1, 1.5, 2 
public int ReadTimeout=0; //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,,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.

Answer 1

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"));
}
//unre to see if setting took correctly
//DCB dcbCommPort2 = new DCB();
//GetCommState(hComm, ref dcbCommPort2);
Opened = true; }
/// <summary>
/// 关闭串口
/// </summary>
///<param name="Close">关闭串口</param>
///<returns>这里填写对返回值的注释或说明</returns> 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"));
}
}
} public 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[i] = Convert.ToByte(("0x" + ByteStrings[i]));
} 
return ByteOut;
}
}
}