VB.net的串口通讯支持总是让人觉得有所不足，在使用VB6的MsComm32.ocx时，很多人都会在VB.net的开发中觉得很困扰。 这里讲述的VB.net串口通讯类使用native代码，并且它是通API调用实现的，你会发现VB.net的串口通讯就是这么简单。   在说明如何使用这个类前，需要说明的是，本类只是一个VB.net的串口通讯演示，你可能需要根据你的情况修改后使用。另外，本类的目的是通过例子教会你在无需ocx控件和第三方组件的支持下用VB.net开发串口通讯程序，所有并没有完善的异常错误处理。   １.初始化并打开串口 创建一个CRs232类的实例，并在调用Open方法前设置好串口通讯参数。 例： Dim moRS232 as New Rs232() With moRs232            .Port = 1                                                    '//　Uses COM1            .BaudRate = 2400                                     '//　波特率 2400            .DataBit = 8                                              '//　8 data bits                                             .StopBit = Rs232.DataStopBit.StopBit_1         '//　停止位 1            .Parity = Rs232.DataParity.Parity_None          '//　无奇偶校验            .Timeout = 500                                                '//超时时间500 ms End With   '// 初始化并打开串口 moRS232.Open () '// 串口打开后，你可以随意地控制DTR/RTS moRS232.Dtr = True moRS232.Rts = True   为了处理异常情况，建议你使用Try...Catch。     ２.发送数据 本类为Rx和Tx准备了两个缓冲区(buffer)，发送数据时，只需要设置TxData属性为你需要发送的数据，然后调用Tx方法就可以了。 例如： moRS232.TxData = txtTx.Text moRS232.Tx()     3.接收数据 先调用Rx方法（参数为您需要从串口读取的字节数），然后读取RxData属性。 例如： moRS232.Rx(10)                       '// 从串口通讯缓冲区里读取10字节 Dim sRead as String=moRs232.RxData   需要注意的是，当本类无法用串口读取到所需的字节数，程序线程在超时异常发生前是锁死的，超时时间通过Timout属性设置。 如果你没有指明需要读取的字节数，本类默认使用512字节来读取缓冲区里的数据。       本文代码由www.codeworks.it提供 版本信息： Project History 1st Public release Beta2 (10/08/2001) Rev.1 (28.02.2002) 1. Added ResetDev, SetBreak and ClearBreak to the EscapeCommFunction constants 2. Added the overloaded Open routine. 3. Added the modem status routines, properties and enum. 4. If a read times out, it now returns a EndOfStreamException (instead of a simple Exception). 5.Compiled with VS.Net final Rev.2 (01.03.2002) Added Async support Rev.3 (07.04.2002) Minor bugs fixed Rev.3a (05/05/2002) Fixed BuildCommmDCB problem Rev.4 (24/05/2002) Fixed problem with ASCII Encoding truncating 8th bit Rev.5 (27/05/2002) Added IDisposable / Finalize implementation Rev.6 (14/03/2003) Fixed problem on DCB fields Initialization Rev.7 (26/03/2003) Added XON/XOFF support Rev.8 (12/07/2003) Added support to COM port number greater than 4 Rev.9 (16/07/2003) Added CommEvent to detect incoming chars/events(!) Updated both Tx/Rx method from Non-Ovelapped to Overlapped mode Removed unused Async methods and other stuff. Rev.10 (21/07/2003) Fixed incorrect character handling when using EnableEvents() Rev.11 (12/08/2003) Fixed some bugs reported by users Rev.12 (01/09/2003) Removed AutoReset of internal buffers and added PurgeBuffer() method Rev.13 (02/09/2003) Update internal stuff now using Win32Exception instead of GetLastError+FormatMessage APIs Rev.14 (14/09/2003) Added IsPortAvailable() function (thanks to Tom Lafleur for the hint) Revised some API declaration Fixed some problems with Win98/Me OS (thanks to Alex Komissarov for the feedback) Rev.15 (24/09/2003) Fixed bug introduced on rev.14 (sorry for that...) Rev.16 (16/10/2003) Added SetBreak/ClearBreak methods for sending break signal over the line. Rev.17 (02/11/2003) Fixed incorrect field on COMMCONFIG Structure. Rev.18 (03/03/2004) Fixed bug causing troubles accessing already in use ports (folks, thanks for the feedback!) Rev.19 (08/04/2004) Fixed bug on DTR property (thanks to Charles-Olivier Théroux) Rev.20 (12/07/2004) CommEvent is no more raised on a secondary thread (please note that this is valid only if event handler is not associated with a static method) pEventsWatcher now uses a background thread Rev.21 (24/10/2004) Fixed EscapeCommFunction declaration Fixed incorrect Pariti enum entry Rev.22 (05/03/2005) Fixed memory leak causing random program termination without any message. Thanks to Ralf Gedrat for testing this scenario. Rev.23 (05/04/2005) Fixed bug DisableEvents not working bug (Thanks to Jean Bédard) 返回

TRT7H-KD36T-FRH8D-6QH8P-VFJHQ