通用串口通信类
以前串口通信一直用AxInterop.MSCommLib第三方串口通信类,但是发现那个东西用着很麻烦,因为需要设置ActiveX控件的持久状态OcxState,这个东西又蛋疼的一般在Winform的Designer里面,随意调整一下界面的布局,那个OcxState的设定就不见了。。。还有个蛋疼的地方就是打开和关闭串口需要比较久的时间。
于是我就想要自己写一个串口通信类,就叫做SerialCommunication。
首先需要一些DllImport
[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();
然后需要一些struct
[StructLayout(LayoutKind.Sequential)] public struct CommTimeouts { public UInt32 ReadIntervalTimeout; public UInt32 ReadTotalTimeoutMultiplier; public UInt32 ReadTotalTimeoutConstant; public UInt32 WriteTotalTimeoutMultiplier; public UInt32 WriteTotalTimeoutConstant; } [StructLayout(LayoutKind.Sequential)] public struct Dcb { public Int32 DCBlength; public Int32 BaudRate; public Int32 PackedValues; 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 wReserved1; } [StructLayout(LayoutKind.Sequential)] public struct Overlapped { public UIntPtr Internal; public UIntPtr InternalHigh; public UInt32 Offset; public UInt32 OffsetHigh; public IntPtr hEvent; }
最后实现开关读写串口即可。开串口只需打开串口,设置串口两步操作,打开串口可能会失败,原因一般是该串口没有设备连接或者正在被其他设备使用中,设置串口也有可能会失败,原因一般是设置的参数不正确或者不够。关串口只需要执行CloseHandle即可
public void Open() { // OPEN THE COMM PORT. _hComm = CreateFile("COM" + PortNum, GenericRead | GenericWrite, 0, 0, OpenExisting, 0, 0); // IF THE PORT CANNOT BE OPENED, BAIL OUT. if (_hComm == InvalidHandleValue) { throw (new Exception("Port Open Failure")); } CommTimeouts ctoCommPort = new CommTimeouts { ReadTotalTimeoutConstant = ReadTimeout }; if (!SetCommTimeouts(_hComm, ref ctoCommPort)) { throw (new Exception("Bad Timeout Settings")); } Dcb dcb = new Dcb(); GetCommState(_hComm, ref dcb); dcb.BaudRate = BaudRate; dcb.Parity = Parity; dcb.ByteSize = ByteSize; dcb.StopBits = StopBits; if (!SetCommState(_hComm, ref dcb)) { throw (new Exception("Bad Com Settings")); } } public void Close() { if (_hComm != InvalidHandleValue) { CloseHandle(_hComm); } }
读串口执行ReadFile即可,可以在调用的地方开一个线程不断的读串口,不过需要考虑效率问题。写串口执行WriteFile即可,每次读、写串口不需要先关闭再打开串口,那样的话也会浪费效率,但是若串口号或者串口配置修改了,则需要关闭并重新打开串口。