commport.cs

利用rs232类进行串口的读写操作,并在windows下显示读写的数据.开发环境:VS.NET2003

using System;
using System.Runtime.InteropServices;


	/// <summary>
	/// commport 的摘要说明。
	/// </summary>
namespace WindowsApplication2
{
	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;

		public int intcount=1;

		// System.Collections.ArrayList allList = new System.Collections.ArrayList();


		//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;

		~CommPort()

		{

		}

		[StructLayout(LayoutKind.Sequential)] private struct DCB
		{
			public int DCBlength;
			public int BaudRate;
			public int Bits1;
			public Int16 wReserved;
			public Int16 XonLim;
			public Int16 XoffLim;
			public byte ByteSize;
			public byte Parity;
			public byte StopBits;
			public byte XonChar;
			public byte XoffChar;
			public byte ErrorChar;
			public byte EofChar;
			public byte EvtChar;
			public Int16 wReserved2;

		}



		[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;

		}

		[StructLayout(LayoutKind.Sequential)]
			public struct COMSTAT 
		{
			public int fCtsHold;
			public int fDsrHold;
			public int fRlsdHold;
			public int DWORD;
			public int fXoffHold;
			public int fXoffSent;
			public int fEof;
			public int fTxim;
			public int fReserved;
			public int cbInQue;
			public int cbOutQue;
		} 

		[DllImport("kernel32.dll")]

		public static extern int ClearCommError(
			int hFile,
			ref uint lpError,
			ref COMSTAT lpComstat
			);

		[DllImport("kernel32.dll")]

		public 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

			[In] 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")]

		public static extern bool CloseHandle(

			int hObject // handle to object

			);

		[DllImport("kernel32.dll")]

		private static extern uint GetLastError();

		public void Open()

		{

			try

			{

				this.Opened = false;

				DCB dcbCommPort = new DCB();
		

				dcbCommPort.DCBlength = Marshal.SizeOf(dcbCommPort);

		
				/*dcbCommPort.XoffLim=50;

				dcbCommPort.XonLim=50;

				dcbCommPort.XonChar = (char)17;

				dcbCommPort.XoffChar = (char)19;
				*/

		
				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;

				dcbCommPort.Bits1 = 21393;

				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("can not open specific port！"));

				}

				//unremark to see if setting took correctly

				//DCB dcbCommPort2 = new DCB();

				//GetCommState(hComm, ref dcbCommPort2);

				//GetCommState(hComm, ref dcbCommPort);

				//why error??? why can i get 21393???
				Opened = true;

			}

			catch (Exception ee)

			{

				throw new Exception("fail in opening port：" + ee.Message);

			}

		}

		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;

				COMSTAT stat = new COMSTAT();				

				uint Error=0;

				ClearCommError(hComm,ref Error,ref stat);

				OutBytes = new byte[0];
			
				if(stat.fDsrHold>0)
				{
					ReadFile(hComm,BufBytes,stat.fDsrHold,ref BytesRead,ref ovlCommPort);				
                    
					OutBytes = new byte[BytesRead];
										
					Array.Copy(BufBytes,OutBytes,BytesRead);
				}

				// System.Diagnostics.Debug.WriteLine("byte------"+this.intcount++);

			}

			else

			{

				throw(new ApplicationException("port is 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("port is not open！"));

			}

		}

	}
}